Forum Index Register Members List Events Mark Forums Read Help

 International Skeptics Forum 9-11 Presentation at NMSR, May 19 2010

 Notices Sadly I have to announce that Locknar is leaving the moderating team. He's contributed massively to keeping this place going over the years. Thanks for all your hard work especially dealing with the new registrations (yeah really thanks for leaving me with that!)

 Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
 Tags Dave Thomas , richard gage , wtc collapse

 20th August 2010, 06:35 PM #401 triforcharity Banned   Join Date: Jun 2009 Posts: 13,961 Originally Posted by dgm pssssst............your talking to yourself. out of your ass. ftfy. :d
 20th August 2010, 06:54 PM #402 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by The Almond And with that, I bow out. If we can't agree on this, there's nothing more to discuss. Mackey was right, you can't fix stupid. Almond, I've watched your impressive (if ultimately futile) effort here, and thought that I would give it a try (I might be a noob, but I've got a little game... ) Quote: Originally Posted by ergo OMFG. The bowling ball does not have the same kinetic energy or momentum if it is pieces of bowling ball. What part of this don't you understand? When it falls to the floor (which was not the analogy I used) both the ball and the floor must absorb the impact. Got it? Ergo, Would you agree that a 5 kilo bowling ball moving at, say 100 m/s has the same kinetic energy as 5 kilos of bowling ball bits moving at 100 m/s? (Namely they both have 50 kiloJoules of kinetic energy.) The same is true of the upper block, whether it is intact or in bits, right? Now there is some energy loss due to energy to eject materials and loss of mass, but let's set that aside for now. Here is what I believe happened upon impact with the ground (this is simpler than the impact of the upper block with the lower block, so it's a good place to start - please let me know what you don't agree with or what I'm not considering that you were trying to imply with your bowling ball impact example. (The exact numbers I'm using are not important, but I like to get a ballpark feel for the quantities involved). Assume that WTC1 had 400 gigaJoules of gravitational potential energy on the morning of 9/11 and that it collapsed in 12.59s resulting in a seismic event measuring 2.3 on the Richter scale. At the moment before the crash reached ground level there was a mass of debris traveling down at about 66 m/s which translates to about 215 GJ of kinetic energy (the rest already having been dissipated in destroying the structure of the building, pulverizing concrete, ejecting the dust cloud and debris, etc. After impact there was a stationary pile of debris, so we will treat the impact as if it were a single inelastic collision. Since there is no motion after the impact, 215 GJ of kinetic energy was dissipated. Where did that energy go? Well, a negligible amount went into vibrations in the air (sonic energy), roughly 12 GJ went into vibrations in the Earth (seismic energy) and the rest was converted into thermal energy in the rubble and the ground via internal friction due to the deformation of materials. Do you agree with this analysis?
 20th August 2010, 07:00 PM #403 Sam.I.Am Illuminator     Join Date: Apr 2009 Posts: 4,627 Welcome Slartibartfast. You can't argue with someone who doesn't listen even after numerous people have shown in many different ways that he's wrong, but good luck trying. Try not to get too many splinters in your forehead while slamming your head on the desk. The chicks don't dig that look. __________________ "Swift, silent and deadly" was a part of my job description Upon hearing me say that my friend asked me "So you're a fart?"... About my avatar.
 20th August 2010, 07:25 PM #404 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by Sam.I.Am Welcome Slartibartfast. You can't argue with someone who doesn't listen even after numerous people have shown in many different ways that he's wrong, but good luck trying. Try not to get too many splinters in your forehead while slamming your head on the desk. The chicks don't dig that look. Don't worry about me, I've got a hard head and some irrepressible optimism that needs curing...
 20th August 2010, 09:27 PM #405 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by Slartibartfast Almond, Here is what I believe happened upon impact with the ground The impact of what with the ground? Thank you. Quote: Assume that WTC1 had 400 gigaJoules of gravitational potential energy on the morning of 9/11 and that it collapsed in 12.59s resulting in a seismic event measuring 2.3 on the Richter scale. At the moment before the crash... The "crash" of what, again? Thank you. Quote: ... reached ground level there was a mass of debris traveling down at about 66 m/s... How does debris travel down at 66m/s through 80 and 90 intact floors of structural steel and concrete? Thank you. Quote: ...which translates to about 215 GJ of kinetic energy (the rest already having been dissipated in destroying the structure of the building, pulverizing concrete, ejecting the dust cloud and debris, etc. Again, you can't have that kind of velocity accompanying crushing and pulverizing. Quote: After impact, Of what against what? Thank you. Quote: there was a stationary pile of debris, so we will treat the impact of what? Quote: as if it were a single inelastic collision. Since there is no motion after the impact, The impact of what against what? Quote: 215 GJ of kinetic energy was dissipated. Not sure how it matters, but are you picking this value out of your ass? You don't show how you arrive at it. Quote: Where did that energy go? Who cares? Quote: Well, a negligible amount went into vibrations in the air (sonic energy), roughly 12 GJ went into vibrations in the Earth (seismic energy) and the rest was converted into thermal energy in the rubble and the ground via internal friction due to the deformation of materials. Again, how do you arrive at your number, and what is the relevance of this to anything we've been discussing? Thank you. Quote: Do you agree with this analysis? I can hopefully answer that when you explain what it is you're analyzing and why it matters to prove or disprove crush-down, crush-up in the WTC.
 20th August 2010, 09:42 PM #406 Sam.I.Am Illuminator     Join Date: Apr 2009 Posts: 4,627 This is the level of discussion that you can expect here from someone like ergo. Nitpicking the obvious and irrelevant so that they can think that they make points while handwaving away that which is actually relevant. Watch out for the splinters... __________________ "Swift, silent and deadly" was a part of my job description Upon hearing me say that my friend asked me "So you're a fart?"... About my avatar.
 20th August 2010, 10:05 PM #407 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 A lot of "debunkers" seem to specialize in vague and imprecise language and dodging plainly spoken, direct questions. I can only assume it's to mask that 1) they don't really have a clue what they pretend to have a clue about, or 2) they have a clue but know that what they are arguing is indefensible so they mumble vaguenesses, clichés and platitudes, use bizarre, broken logic, and/or hurl insults and accusations in the hopes that you will be too distracted to see the gaping holes.
 20th August 2010, 10:25 PM #408 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Ergo, I am just trying to establish the basic physics of the situation and determine where you disagree with what Almond was saying (you may assume that I agree with Almond). I don't think that a productive debate can occur without agreeing on the ground rules (in this case, the physics involved). Quote: The impact of what with the ground? Thank you. The impact of the falling debris with the ground. Quote: The "crash" of what, again? Thank you. 'Crash' again referring to the impact of the debris with the ground. Quote: How does debris travel down at 66m/s through 80 and 90 intact floors of structural steel and concrete? 66m/s is the speed that an object that traveled from the top of the WTC to the ground in 12.59s at constant acceleration would be going when it hit the ground. Consider it a rough estimate of the average speed of debris upon hitting the ground (Again, the exact value of the numbers are not important - I just find it intuitively helpful. Also, you can't do calculations of without numbers... ) Since the collapse did travel down through 90 or so intact floors in the space of roughly 13s, we know that the collapse front was moving at something like that speed when it impacted ground level. I'm assuming nothing about HOW the debris traveled through all those floors, just that they did travel through all of those floors. Quote: Again, you can't have that kind of velocity accompanying crushing and pulverizing. Why not? The velocity had to be something like that given the time of collapse - this is not meant to be anything more than a very rough estimate (I'm interested in the concepts of energy and momentum as these are what you seem to disagree about, not the exact values of these quantities for the collapse). I can make a case for where all of the gravitational potential energy went in the collapse, but I don't think that it is germane here. Quote: Of what against what? The falling debris impacting the ground. Quote: Not sure how it matters, but are you picking this value [the kinetic energy of the debris before impact] out of your ass? You don't show how you arrive at it. I don't think it matters to this conversation, but I got the number by assuming that the ratio of the value in question to the total GPE was equal to the ratio of the squares of the velocity calculated above and the free-fall impact velocity. Quote: Who cares? [what happened to the energy] Since energy is always conserved, it is a useful quantity in analyzing events like this (plus your disagreement with Almond involved energy). Quote: Again, how do you arrive at your number [~12 GJ of seismic energy], and what is the relevance of this to anything we've been discussing? A seismic event which registers 2.3 on the Richter scale (like the collapse of WTC1) dissipates about 12 GJ of energy. In order to resolve the disagreement over the kinetic energy of the bowling ball/bowling ball pieces we need to consider kinetic energy and what happens to it. Quote: I can hopefully answer that when you explain what it is you're analyzing and why it matters to prove or disprove crush-down, crush-up in the WTC. I'm trying to establish the basics of conservation of energy in order to provide a basis for discussing a crush-down/crush-up collapse. No reasoned debate is possible if the two sides disagree about the physical principles involved.
 20th August 2010, 10:46 PM #409 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by ergo A lot of "debunkers" seem to specialize in vague and imprecise language and dodging plainly spoken, direct questions. I can only assume it's to mask that 1) they don't really have a clue what they pretend to have a clue about, or 2) they have a clue but know that what they are arguing is indefensible so they mumble vaguenesses, clichés and platitudes, use bizarre, broken logic, and/or hurl insults and accusations in the hopes that you will be too distracted to see the gaping holes. I'll do my best to answer any questions you ask - I am attempting to establish a consensus on the physics involved in this discussion which I believe is essential to any sort of reasonable debate. As far as what I do (or don't) have a clue about, I am a mathematical biologist (I have a PhD in math from Duke) who specializes in cell cycle modeling and I have a solid understanding of Newtonian physics from several years as a physics major as an undergrad. I'm not an expert in this, but as I said in my first post, I do have some knowledge in this area. I believe that what I'm arguing is correct and will defend it to the best of my ability, so if you think I'm being vague, I'll gladly explain my arguments better, I'll try to keep the clichés and platitudes to a minimum, keep my logic as clean as possible (as a mathematician I have pretty strong feelings about logic and the idea of 'proof'), and I'll let you focus your attention where you will. As you might have noted from my earlier response, any numbers that I use come from somewhere and I'm always willing to clarify what calculations or sources I used to arrive at any of them.
 20th August 2010, 11:12 PM #410 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by Slartibartfast The impact of the falling debris with the ground. The debris did not impact the ground until the last lower floor, supposedly, was crushed through. That supposed crushing through produced debris which would already be in contact with the ground. So technically, there was no "impact" of debris with the ground. It would be debris with debris. Nor was it "falling". It was supposedly crushing through. This is not just semantics. This is getting the "debunkers" to explain their argument using the terms that were introduced and that exist as the official collapse theory. Quote: 66m/s is the speed that an object that traveled from the top of the WTC to the ground in 12.59s at constant acceleration would be going when it hit the ground. Consider it a rough estimate of the average speed of debris upon hitting the ground ... Since the collapse did travel down through 90 or so intact floors in the space of roughly 13s, we know that the collapse front was moving at something like that speed when it impacted ground level. I'm assuming nothing about HOW the debris traveled through all those floors, just that they did travel through all of those floors. Obviously I don't agree with this model of the collapse. Quote: Why not? The velocity had to be something like that given the time of collapse - I agree that the collapse front, for lack of a better term, descended at that speed. I do not agree that debris moved through a third of a kilometre high of building at that speed. Quote: Since energy is always conserved, it is a useful quantity in analyzing events like this Still waiting to find out what you're analyzing. Quote: A seismic event which registers 2.3 on the Richter scale (like the collapse of WTC1) dissipates about 12 GJ of energy. In order to resolve the disagreement over the kinetic energy of the bowling ball/bowling ball pieces we need to consider kinetic energy and what happens to it. Okay. Quote: I'm trying to establish the basics of conservation of energy in order to provide a basis for discussing a crush-down/crush-up collapse. No reasoned debate is possible if the two sides disagree about the physical principles involved. I'm not sure in what ways you think you have established the "basics", and it sure wasn't a convincing start, but I'll suspend my disbelief for now. Why are you using conservation of energy which is applicable only to isolated systems?
 20th August 2010, 11:13 PM #411 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by Slartibartfast I believe that what I'm arguing is correct and will defend it to the best of my ability, so if you think I'm being vague, I'll gladly explain my arguments better, I'll try to keep the clichés and platitudes to a minimum, keep my logic as clean as possible (as a mathematician I have pretty strong feelings about logic and the idea of 'proof'), and I'll let you focus your attention where you will. As you might have noted from my earlier response, any numbers that I use come from somewhere and I'm always willing to clarify what calculations or sources I used to arrive at any of them. Great.
 21st August 2010, 12:35 AM #412 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by ergo The debris did not impact the ground until the last lower floor, supposedly, was crushed through. That supposed crushing through produced debris which would already be in contact with the ground. So technically, there was no "impact" of debris with the ground. It would be debris with debris. Nor was it "falling". It was supposedly crushing through. This is not just semantics. This is getting the "debunkers" to explain their argument using the terms that were introduced and that exist as the official collapse theory. Each piece of debris was torn loose from the structure of the building and ended its 'career', so to speak, in an inelastic collision with the ground (or the rubble pile). As the purpose of this example is just an attempt to get us both on the same page as far as the physics are concerned, I don't think this point is important to clear up right now (although if you would like to elaborate on what the distinction you're trying to make here is, that's fine by me). Quote: Obviously I don't agree with this model of the collapse. That's a given - as I said, I'm just trying to lay out a scenario in which we can come to a consensus about the physics right now. One question from earlier that you did not answer: do you agree that two objects or groups of objects with the same mass traveling at the same speed have the same kinetic energy? Quote: I agree that the collapse front, for lack of a better term, descended at that speed. I do not agree that debris moved through a third of a kilometre high of building at that speed. That was just an estimate of the speed of the debris immediately before impact - at that point the speed of the mass of debris and the speed of the collapse front would be roughly equivalent regardless of whether or not they attained that speed with or without help (i.e. explosives). Quote: Still waiting to find out what you're analyzing. Until we reach some kind of consensus regarding the physics of energy and momentum, we wont be 'talking the same language' so to speak. (Also, as someone trained in mathematics I have a compulsion to make sure that everyone is using the same definitions. ) Quote: I'm not sure in what ways you think you have established the "basics", and it sure wasn't a convincing start, but I'll suspend my disbelief for now. Why are you using conservation of energy which is applicable only to isolated systems? This comment illustrates exactly why I'm doing this - energy is conserved universally. While the total energy of a system is only conserved if the system is isolated, every instance of work conserves energy while converting it from one form to another or transferring it from one place to another. Unfortunately, I can't give you a link to support this until I've made a few more posts... (any basic physics text or Wikipedia would work, however - pun intended )
 21st August 2010, 12:57 AM #413 dafydd Banned   Join Date: Feb 2008 Posts: 35,398 Originally Posted by Slartibartfast Each piece of debris was torn loose from the structure of the building and ended its 'career', so to speak, in an inelastic collision with the ground (or the rubble pile). As the purpose of this example is just an attempt to get us both on the same page as far as the physics are concerned, I don't think this point is important to clear up right now (although if you would like to elaborate on what the distinction you're trying to make here is, that's fine by me). That's a given - as I said, I'm just trying to lay out a scenario in which we can come to a consensus about the physics right now. One question from earlier that you did not answer: do you agree that two objects or groups of objects with the same mass traveling at the same speed have the same kinetic energy? That was just an estimate of the speed of the debris immediately before impact - at that point the speed of the mass of debris and the speed of the collapse front would be roughly equivalent regardless of whether or not they attained that speed with or without help (i.e. explosives). Until we reach some kind of consensus regarding the physics of energy and momentum, we wont be 'talking the same language' so to speak. (Also, as someone trained in mathematics I have a compulsion to make sure that everyone is using the same definitions. ) This comment illustrates exactly why I'm doing this - energy is conserved universally. While the total energy of a system is only conserved if the system is isolated, every instance of work conserves energy while converting it from one form to another or transferring it from one place to another. Unfortunately, I can't give you a link to support this until I've made a few more posts... (any basic physics text or Wikipedia would work, however - pun intended ) The inverted commas around career were not needed,the word was used in the right context.Things career along,not careen,as they do in the States.Careen means to drag a ship onto dry land and scrape the barnacles and seaweed off the bottom.Sorry for the diversion,back on topic.
 21st August 2010, 01:22 AM #414 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by dafydd The inverted commas around career were not needed,the word was used in the right context.Things career along,not careen,as they do in the States.Careen means to drag a ship onto dry land and scrape the barnacles and seaweed off the bottom.Sorry for the diversion,back on topic. Noted.
 21st August 2010, 03:42 AM #415 TruthersLie This space for rent.     Join Date: Jun 2009 Posts: 3,715 Originally Posted by dafydd The inverted commas around career were not needed,the word was used in the right context.Things career along,not careen,as they do in the States.Careen means to drag a ship onto dry land and scrape the barnacles and seaweed off the bottom.Sorry for the diversion,back on topic. Just like a Brit to abuse the english language so. As I tell all of my brit friends, I need a british to english dictionary because they have made such a ham of it. career is what you do for a living over a long period of time. A buoy is pronounced booo eeeee, not BOY You don't need to add a U to every O in words... hence it is honor, color. And lastly, your interesting use of pants, panties, jumpers, trainers and the vulgar FANNY. Tsk tsk tsk. __________________ "There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
 21st August 2010, 03:53 AM #416 bill smith Philosopher     Join Date: Feb 2009 Posts: 8,408 Originally Posted by TruthersLie Just like a Brit to abuse the english language so. As I tell all of my brit friends, I need a british to english dictionary because they have made such a ham of it. career is what you do for a living over a long period of time. A buoy is pronounced booo eeeee, not BOY You don't need to add a U to every O in words... hence it is honor, color. And lastly, your interesting use of pants, panties, jumpers, trainers and the vulgar FANNY. Tsk tsk tsk. I always see American as a kind of English shorthand. Often convenient but seldom satisfactory. That's why they say that England and America are two countries seperated by a common language I suppose. __________________ *Think WTC7 - You cannot make the four corners of a table fall together unless you cut the four legs together *A kitchen table judgement on a world scale is enough * To Citizens: 'There comes a time when silence is betrayal' Last edited by bill smith; 21st August 2010 at 03:55 AM.
 21st August 2010, 05:25 AM #417 DGM Skeptic not Atheist     Join Date: May 2007 Location: West of Northshore MA Posts: 24,586 Originally Posted by ergo The debris did not impact the ground until the last lower floor, supposedly, was crushed through. That supposed crushing through produced debris which would already be in contact with the ground. So technically, there was no "impact" of debris with the ground. It would be debris with debris. Nor was it "falling". It was supposedly crushing through. This is not just semantics. This is getting the "debunkers" to explain their argument using the terms that were introduced and that exist as the official collapse theory. You really shouldn't use the term "technically". "Technically" every piece of rubble was impacting the ground from the very beginning of the collapse. Just like rain falling on the roof of a building is in fact "impacting" the ground. It's doing this through the structure of the building. I won't even start with "falling". So "technically" your above paragraph is wrong. Remember "rock and a hard place". __________________ "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41
 21st August 2010, 06:30 AM #418 pgimeno Illuminator     Join Date: Feb 2009 Location: Spain Posts: 3,322 Originally Posted by ergo A lot of "debunkers" seem to specialize in vague and imprecise language and dodging plainly spoken, direct questions. I can only assume it's to mask that 1) they don't really have a clue what they pretend to have a clue about, or 2) they have a clue but know that what they are arguing is indefensible so they mumble vaguenesses, clichés and platitudes, use bizarre, broken logic, and/or hurl insults and accusations in the hopes that you will be too distracted to see the gaping holes. Says the pot to the kettle. You're accusing the people who participate here of doing what you are doing. Please address post #368 instead of dodging it every time I ask. It's central to make you understand how wrong you are. If you agree that the top reaches the street level intact, then you are accepting that the crush-down/crush-up model is accurate. If you don't agree, it shows you're wrong in your belief that rubble is not able to crush. That's probably why you're dodging it. And the question stated in that post is also relevant to understand why it's irrelevant that the top is intact or is in the form of rubble: what significant difference would it make for the rubble layer to be driven by an intact upper block or by more rubble? You can dodge, but you can't escape. And here's another new question for you, this one about pure physics: You say that a bowling ball in pieces wouldn't have the same kinetic energy or momentum as a whole bowling ball (I assume you mean with the same total mass and velocity). Please give a quantification of it in this simplified example: imagine a bowling ball split in half, with the two halves moving together. 1. How much energy do the combined two halves do, as compared to a whole ball? 2. Assuming you can survive an impact of half a bowling ball but not a whole bowling ball, would you survive an impact of the two halves together? __________________ Ask questions. Demand answers. But be prepared to accept the answers, or don't ask questions in the first place.
 21st August 2010, 08:39 AM #419 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by Slartibartfast Each piece of debris was torn loose from the structure of the building and ended its 'career', so to speak, in an inelastic collision with the ground (or the rubble pile). Much of the debris is in the form of dust, as we can see by the dust plumes in the pictures and that then covered Manhattan for days afterward, and as evidenced by the absence of larger chunks of matter at Ground Zero that one would normally find in natural collapses. That dust did settle of course, but it was not part of the "falling" debris that you are trying to include in this discussion of mass, and I don't think there has been an accurate estimate of how much of the buildings were converted into this dust, or what I like to call powder. Just sayin'. Large amounts of other debris, as we know, fell outside the building, yes, landing on the ground, outside the building's footprint. Quote: That's a given - as I said, I'm just trying to lay out a scenario in which we can come to a consensus about the physics right now. One question from earlier that you did not answer: do you agree that two objects or groups of objects with the same mass traveling at the same speed have the same kinetic energy? I will agree that two objects with the same mass traveling at the same speed will have the same momentum. I am not clear in this example of how momentum would be distinct from kinetic energy. I also don't see the point of bringing into the discussion "groups" of objects. Just discuss the objects on their own. Quote: While the total energy of a system is only conserved if the system is isolated, every instance of work conserves energy while converting it from one form to another or transferring it from one place to another. Okay.
 21st August 2010, 08:50 AM #420 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by pgimeno And the question stated in that post is also relevant to understand why it's irrelevant that the top is intact or is in the form of rubble: what significant difference would it make for the rubble layer to be driven by an intact upper block or by more rubble? The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again.
 21st August 2010, 09:07 AM #421 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Slartibartfast, it might be helpful if you made your point first, and then we can go back and pick it out step by step. I would still let you lead the discussion, but I might be less defensive in my answers if I knew where you were going. It's also the way scientific papers and discussions are organized, as well as legal ones. It's also a courtesy. Thanks.
 21st August 2010, 09:16 AM #422 BigAl Philosopher     Join Date: Jun 2007 Posts: 5,397 Originally Posted by ergo The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again. Physics continues to elude you. __________________ ------ Eric Pode of Croydon Chief Assistant to the Assistance Chief, Dept of Redundancy Dept.
 21st August 2010, 09:33 AM #423 Slartibartfast Student   Join Date: Aug 2010 Posts: 27 Originally Posted by ergo Slartibartfast, it might be helpful if you made your point first, and then we can go back and pick it out step by step. I would still let you lead the discussion, but I might be less defensive in my answers if I knew where you were going. It's also the way scientific papers and discussions are organized, as well as legal ones. It's also a courtesy. Thanks. The two main concepts in physics relevant to the collapse are momentum and kinetic energy. You seem hesitant to allow that two things moving at the same speed with the same mass have the same kinetic energy - this is a problem since momentum is only part of the story. I'm just trying to establish a context of how momentum and kinetic energy work so that we can both argue our theories within that context. That's all - I just don't find a discussion where there is no agreement on basic physics very interesting and I don't think that a reasonable discussion about crush-down/crush-up can be had without that agreement regarding the physics in play. I don't have time right now, but I'll answer your other posts later.
 21st August 2010, 09:46 AM #424 TruthersLie This space for rent.     Join Date: Jun 2009 Posts: 3,715 Originally Posted by ergo Much of the debris is in the form of dust, as we can see by the dust plumes in the pictures and that then covered Manhattan for days afterward, and as evidenced by the absence of larger chunks of matter at Ground Zero that one would normally find in natural collapses. That dust did settle of course, but it was not part of the "falling" debris that you are trying to include in this discussion of mass, and I don't think there has been an accurate estimate of how much of the buildings were converted into this dust, or what I like to call powder. Just sayin'. You mean the large amounts of debris which was 6 stories tall across the entire wtc complex? That "absence of larger chunks of matter?" You are right. there is no debris here none nope... no debris. The same massive debris piles which you can easily find images of? Is your google fu that weak? I'm still waiting for you to explain to me how that car was crushed. or how snow can crush a building, or mud can destroy a damn... Quote: Large amounts of other debris, as we know, fell outside the building, yes, landing on the ground, outside the building's footprint. Great. Provide any technical definition fo what "large amounts" are. How big as a % of the buildings mass? See... statements like "large amounts" are insufficient for any technical/scientific discussion. __________________ "There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers) Last edited by TruthersLie; 21st August 2010 at 09:48 AM.
 21st August 2010, 10:09 AM #425 bill smith Philosopher     Join Date: Feb 2009 Posts: 8,408 Originally Posted by BigAl Physics continues to elude you. Remember the good old days Al ? This would be meat and drink to Heiwa, the banned Swedish Naval Architect, structural damage analyst and sometime advisor to the UN who swept all before him here on the jref prior to his banning. '' Here iis a random link to his thread 'wWhy a one-way crush down is not possible '' Much of the stuff that is being argued here is covered there too I think in case anyone wants to leaf through it for info . http://www.internationalskeptics.com...140047&page=18 __________________ *Think WTC7 - You cannot make the four corners of a table fall together unless you cut the four legs together *A kitchen table judgement on a world scale is enough * To Citizens: 'There comes a time when silence is betrayal' Last edited by bill smith; 21st August 2010 at 10:21 AM.
 21st August 2010, 12:33 PM #426 beachnut Penultimate Amazing     Join Date: Oct 2006 Location: Dog House Posts: 24,923 Originally Posted by bill smith Remember the good old days Al ? This would be meat and drink to Heiwa, the banned Swedish Naval Architect, structural damage analyst and sometime advisor to the UN who swept all before him here on the jref prior to his banning. '' Here iis a random link to his thread 'wWhy a one-way crush down is not possible '' ... Heiwa? His work was called nonsense and delusional in a real engineering journal. You like delusions, no wonder you fall for the insanity of Heiwa's lies and moronic work.
 21st August 2010, 02:37 PM #427 Lyrandar Thinker     Join Date: Apr 2010 Posts: 211 Originally Posted by Slartibartfast Almond, I've watched your impressive (if ultimately futile) effort here, and thought that I would give it a try (I might be a noob, but I've got a little game... ) Slartibartfast - welcome, and good luck. I tried something similar with jammonius a few months ago, but I gave up after a while. I guess we'll see how this turns out. I suppose I may as well give it a try also. Originally Posted by ergo The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again. Yeah, but in order to flow down and to the sides, something has to change those velocity and momentum vectors off to the sides. Impacts with the top of the intact lower portion might work, as well as impacts with other pieces of rubble sitting on it. Either of those, however, will result in some amount of energy ending up in that intact top floor of the lower portion. Enough of that, and that floor will fail and drop everything, even if some of the rubble has been deflected off to the side. Then that floor's mass gets added to the rubble pile falling on the floor below, which may make up for the mass lost off to the sides while it was failing. Your argument is, if I understand it correctly, that enough mass would have been deflected off to the sides to create a net reduction in the mass striking the floors below, and that this reduction would have happened at a quick enough rate to have saved most of the lower portion of the building, assuming nothing but gravity. I admit I am taking posters such as Almond at their word on this, but the impression I have got from reading this thread is that the numbers defining the building's strength and the force imparted by the rubble do not support that idea at all. Do your calculations indicate otherwise and/or why should I believe yours instead of the others?
 21st August 2010, 09:35 PM #428 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by Lyrandar Yeah, but in order to flow down and to the sides, something has to change those velocity and momentum vectors off to the sides. It's a *********** rubble pile. I can't believe this is actually being taken as a serious argument. Quote: Your argument is, if I understand it correctly, that enough mass would have been deflected off to the sides to create a net reduction in the mass striking the floors below, and that this reduction would have happened at a quick enough rate to have saved most of the lower portion of the building, assuming nothing but gravity. My argument is that rubble sitting on top of a building cannot crush it. This is kindergarten-level understanding. Quote: I admit I am taking posters such as Almond at their word on this, but the impression I have got from reading this thread is that the numbers defining the building's strength and the force imparted by the rubble do not support that idea at all. Do your calculations indicate otherwise and/or why should I believe yours instead of the others? I have not seen any numbers on the force imparted by the rubble. Nor would I care, except to see who is willing to risk their career in claiming such utter nonsense.
 21st August 2010, 09:47 PM #429 triforcharity Banned   Join Date: Jun 2009 Posts: 13,961 Originally Posted by ergo My argument is that rubble sitting on top of a building cannot crush it. This is kindergarten-level understanding. Yes, kindergarten children do not understand structural loading, loads, and dynamic V static. Apparently, neither do you.....
 22nd August 2010, 04:14 AM #430 TruthersLie This space for rent.     Join Date: Jun 2009 Posts: 3,715 Originally Posted by ergo {lots of handwaving which has been deleted} My bowling ball argument is based on reality. How the impact from the bowling ball refers through the person's body to the ground is irrelevant to the point I was making. The bowling ball falling on someone's head clearly will fracture their skull. The fragments of bowling ball will not. There is no unconsidered factor here. If there is, please identify it specifically. So then again you state that a 10lbs of debris will not fracture someones skull whereas a 10lbs intact bowling ball will. Is that correct? I bet that makes people who are working with sand, snow and water very happy... especially those who work with thousands of pounds of it at a time becaue those are small fragments... and hence (in your world) incapable of hurting or killing them. Have you notified the proper engineering channels of your discovery? (how was that car crushed again? You have never answered) Quote: I already pointed out where energy is lost in the system. To say that it was only converted into "heat" and "sound" is too stupid to comment to. Do civil engineers not have to know any physics? I don't think you're an engineer. If you are, you are knowingly lying. Then I'm sure you can show how much energy was lost to the system. I'm sure you can show with math the amount of debris which did not impact the towers and was ejected outwards and how that loss of mass changed the dynamics enough to arrest the collapse. When will you be providing that pdoh/stundie? __________________ "There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
 22nd August 2010, 04:33 AM #431 TruthersLie This space for rent.     Join Date: Jun 2009 Posts: 3,715 Originally Posted by ergo {more handwaving deleted} Which falls to the ground faster, Mr. Civil Engineer? Which one would you stand under? Hmmm? __________________ "There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
 22nd August 2010, 04:36 AM #432 TruthersLie This space for rent.     Join Date: Jun 2009 Posts: 3,715 Originally Posted by ergo I've actually found that the insults tossed at me tend to suggest that I don't understand the very principles that, in fact, debunk the official collapse hypothesis. It must be some new kind of 21st century newspeak (or maybe it's just old) to insist that the "debunker" understands something he/she clearly doesn't, and that the opponent, who clearly and demonstrably does understand, "doesn't". I know it's cliche to say it, but it is an Orwellian experience trying to debate "debunkers". Wonderful. Then you can easily point me to any peer reviewed engineering or physics papers ANYWHERE IN THE WORLD, IN ANY LANGUAGE which states that NIST is wrong. Even that portions of NIST are wrong. Please provide one. Just one. I'm not asking for much. (hell I have 4 peer reviewed journal articles on my CV...) __________________ "There are submissions to the Journal of 9/11 Studies, but that's about as convincing as submissions to the Journal of Intelligent Design Studies." –Noam Chomsky (and this can be said of ANY and all twoof papers)
22nd August 2010, 04:47 AM   #433
pgimeno
Illuminator

Join Date: Feb 2009
Location: Spain
Posts: 3,322
Originally Posted by ergo
Much of the debris is in the form of dust, as we can see by the dust plumes in the pictures and that then covered Manhattan for days afterward, and as evidenced by the absence of larger chunks of matter at Ground Zero that one would normally find in natural collapses. That dust did settle of course, but it was not part of the "falling" debris that you are trying to include in this discussion of mass, and I don't think there has been an accurate estimate of how much of the buildings were converted into this dust, or what I like to call powder. Just sayin'.
Here's an estimate on the distribution of sizes of concrete particles, according to Dr. Greening, for a 10x10x10cm cube of concrete impacted at the energies estimated from the collapse:

10cm-1cm: 30%
1cm-1mm: 20%
1mm-100μm: 15%
100μm-10μm: 10%
Less than 10μm: 25%
Source

I think you will agree that only the smaller particles would have it easier to escape due to air pressure. The bigger ones would have more difficulty to escape that quickly due to their inertia at a minimum.

Originally Posted by ergo
Large amounts of other debris, as we know, fell outside the building, yes, landing on the ground, outside the building's footprint.
Now it would just be a baseless claim to say that most of the rubble spilled outside the towers' footprint. If, say, half of the rubble stood within it, then there would have been more than enough mass to crush the rest of the building, then turning more of it into rubble which couldn't escape that easily at first.

But you haven't yet addressed the point that in the demolitions I showed you the top falls basically intact, as Bažant predicted, so why should the WTC towers' top sections turn completely into rubble *before* starting to crush down, contradicting what is actually seen in the videos? So far your only argument has been your own belief, while Bažant proves his point using sound physics arguments and math.

Originally Posted by ergo
The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again.
I got news for you. Debris is not a fluid. Neither is dust. See the difference in this video:

 YouTube Video This video is not hosted by the ISF. The ISF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website. I AGREE

These are mountains of dustified concrete and soil. They don't spread along the whole floor as a fluid would do. Debris has much more difficulty to flow than fluids, because it's not a fluid. Ultimately it settles and ceases flowing far before a fluid would.

The time needed for the dust to leave the footprint (not the heavier parts, e.g. the core columns that failed and stayed within the footprint or the steel plates and trusses of the flooring system, of which little were seen flying outside, if any, or the heavier pieces of concrete from the floors, of which there were large chunks visible on the surface of the rubble pile) would be compensated by the speed at which rubble was generated (110 floors in, say, at most 22 seconds is about 5 floors a second; the faster the collapse speed the faster the rubble was generated). Your argument that "[r]ubble also cannot stay vertical as a mass for any significant length of time" is thus moot.

So, you'd need a credible argument if you want to state that the rubble left the building before being able to crush it. So far you've just stated a belief, which is contradicted by every piece of evidence, e.g. the "crush-up" prior to "crush-down" did not happen as anyone can see, besides the fact that physics predicts it wouldn't happen.

As for your argument that rubble is just a collection of individual parts that together can't damage a structure more than each individual part by itself, you've already been indicated how wrong you are. As a reminder, the rubble on the front of the collapse was driven by the weight of the rubble which was right over it and remained there, which was a significant part, if only due to the laws of inertia. What you see being ejected is mostly dust (which doesn't account for more than 50% of the existing concrete) and the perimeter panels (which were "peeled off"). The building was more than that though.
__________________

 22nd August 2010, 07:13 AM #434 bill smith Philosopher     Join Date: Feb 2009 Posts: 8,408 Didn't Greening estimate that there was 120,000 tons of dust in the streets afer the collapses ? Say 400 tons from each floor of both Twin Towers. That's a very considerabe reduction in mass all on its own.Then there was almost no wire mesh reinforcing matting of which there were two layers in each floor. That's 9.2 million square feet per Tower that's also missing. Then there is 4.5 million square feet of floor decking per Tower that does not appear in the rubble. Core columns ?....there should be 10 MILES of them....massive core columns that are also largely missing. Concrete ? Hardly enough to make a decent rockery. Sure the centre of the footprint ogf WTC1 was virtually bare. __________________ *Think WTC7 - You cannot make the four corners of a table fall together unless you cut the four legs together *A kitchen table judgement on a world scale is enough * To Citizens: 'There comes a time when silence is betrayal' Last edited by bill smith; 22nd August 2010 at 07:21 AM.
 22nd August 2010, 07:16 AM #435 DGM Skeptic not Atheist     Join Date: May 2007 Location: West of Northshore MA Posts: 24,586 Originally Posted by bill smith Didn't Greening estimate that there was 120,000 tons of dust in the streets afer the collapses ? Say 400 tons from each floor of both Twin Towers. That's a very considerabe reduction in mass all on its own.Then there was almost no wire mesh reinforcing matting of which there were two layers in each floor. That's 9.2 million square feet per Tower that's also missing. Then there is 4.5 million square feet of floor decking per Tower that does not appear in the rubble. Core columns ?....there should be 10 MILES of them....massive core columns that are also largely missing. Concrete ? Hardly enough to make a decent rockery. Sure the centre of the footprint ogf WTC1 was virtually bare. Not that I'm aware of. I think you need to look that up again. __________________ "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41
 22nd August 2010, 07:21 AM #436 ergo Illuminator     Join Date: Aug 2010 Posts: 4,339 Originally Posted by pgimeno Now it would just be a baseless claim to say that most of the rubble spilled outside the towers' footprint. If, say, half of the rubble stood within it, then there would have been more than enough mass to crush the rest of the building, then turning more of it into rubble which couldn't escape that easily at first. Please show the energetic analysis that indicates that rubble can crush an 80 or 90-storey building. Quote: But you haven't yet addressed the point that in the demolitions I showed you the top falls basically intact, as Bažant predicted, I didn't know Bazant made predictions about demolitions.Why wouldn't he just ask demolitioners? What else does he predict? How long he'll remain employed at Northwestern? Quote: I got news for you. Debris is not a fluid. Neither is dust. See the difference in this video: Please cite where I claim that rubble is a fluid. Quote: As for your argument that rubble is just a collection of individual parts that together can't damage a structure more than each individual part by itself, you've already been indicated how wrong you are. As a reminder, the rubble on the front of the collapse was driven by the weight of the rubble which was right over it and remained there, which was a significant part, if only due to the laws of inertia. "Which was a significant part".... "because we need it to be!" Magically, stationary inertia overcomes gravity in this argument, but only around the sides of the rubble, so that it doesn't spill over the sides! Maybe you should answer TrutherLie's question to me: Which would you rather stand under, a kilo of bricks or a kilo of feathers?
 22nd August 2010, 07:33 AM #437 bill smith Philosopher     Join Date: Feb 2009 Posts: 8,408 Originally Posted by DGM Not that I'm aware of. I think you need to look that up again. Check it out here. Greening posts as 'Apollo'. http://www.internationalskeptics.com...ad.php?t=93119 __________________ *Think WTC7 - You cannot make the four corners of a table fall together unless you cut the four legs together *A kitchen table judgement on a world scale is enough * To Citizens: 'There comes a time when silence is betrayal' Last edited by bill smith; 22nd August 2010 at 07:37 AM.
 22nd August 2010, 07:52 AM #438 DGM Skeptic not Atheist     Join Date: May 2007 Location: West of Northshore MA Posts: 24,586 Originally Posted by bill smith Check it out here. Greening posts as 'Apollo'. http://www.internationalskeptics.com...ad.php?t=93119 Ah yes I remember now . Maybe you should talk to people that were actually there before you talk about "missing" material. I know you've seen pictures that disprove your "thoughts" so I won't go there. __________________ "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41
 22nd August 2010, 07:58 AM #439 bill smith Philosopher     Join Date: Feb 2009 Posts: 8,408 Originally Posted by DGM Ah yes I remember now . Maybe you should talk to people that were actually there before you talk about "missing" material. I know you've seen pictures that disprove your "thoughts" so I won't go there. I trust pictures a lot more than I trust people whe it comes to 9/11 DGM. Especially early pictures where they may have been revealing more than they knew. Do you have any panoramic photos of the rubble pile in the footprint of WTC1 ? No closeups Wide or panoramic shots only. __________________ *Think WTC7 - You cannot make the four corners of a table fall together unless you cut the four legs together *A kitchen table judgement on a world scale is enough * To Citizens: 'There comes a time when silence is betrayal'
 22nd August 2010, 08:06 AM #440 DGM Skeptic not Atheist     Join Date: May 2007 Location: West of Northshore MA Posts: 24,586 Originally Posted by bill smith I trust pictures a lot more than I trust people whe it comes to 9/11 DGM. Especially early pictures where they may have been revealing more than they knew. Do you have any panoramic photos of the rubble pile in the footprint of WTC1 ? No closeups Wide or panoramic shots only. Why no "close-ups"? Wouldn't it be hard to see the stuff your looking for in wide or panoramic photos (IE wire mesh and mangled floor pans)? __________________ "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41

International Skeptics Forum

 Bookmarks Digg del.icio.us StumbleUpon Google Reddit