hi i'm david chandler and i've been very involved with the nine eleven truth movement for several years now a few years ago when i first heard that the prospect that the buildings in new york city were brought down with explosives i was initially quite skeptical of this because i didn't see any compelling reason to see why this had to be the case but what i did in response to this idea is i started looking more carefully at the videos and to see what could see like is there evidence that this is is there a strong reason to believe that this is actually what happened and i started just on a qualitative basis of looking at things and then little by little i got more in the measurement and i brought my physics background into this i'm a physics teacher i've taught college level and high school physics and i bring that into my work because you'll see as we go along what i've done is i've posted the short video clips on you tube and what we're going to do on this d v d is string these together with commentary and to try to give the bigger picture the little clips on each one is a like a single theme but i'm going to try and weave them together the first clip is called north tower exploding and all it is is an infinite loop just showing the north tower coming down repeatedly and in the process i'll be narrating the things that i'm seeing what you need to do is see what you are seeing and use this just as an opportunity to open your eyes a little bit to starting point and science is observation what you are seeing here is what happened to the north tower of the world trade center second of three buildings to collapse on nine eleven two thousand and one i use the word collapse words can be deceptive but do you really see happening here there's a tremendous amount of falling debris under the canopy of debris you see the rapid sequence of explosive ejections of material some of the jets have been clocked at over one hundred miles per hour i'll call them explosions because it's hard to find other words that describe what we're seeing here explosions are not isolated and few there continuous and widespread it moved progressively down the faces of the building keeping pace with the falling debris perhaps you can imagine a natural cause i can't notice that the explosions are occurring on multiple floors at once over a wide zone not in a floor by floor sequence but might be explained by pancaking collapse noticed there are explosions far below the point of collapse some are isolated and focused these are often referred to as squibs and are commonly seen in controlled demolitions however this is not a standard controlled demolition the building is being progressive really destroyed from the top down by waves of explosions creating a huge debris field the destruction is in a way i not just in one way the most obvious is a rapid sequence of explosions near the visible corner of the building simultaneously we can see another wave of explosions much further down the face of the building under the canopy of falling debris noticed the both waves of explosions progress down the face of the building nearly keeping pace with falling debris just a few feet away slabs of concrete did not fall to the ground and smashed to dust there is almost no concrete in the rubble pile notice that the concrete is being forcefully ejected outwards from the sides of the building already pulverized to dust noticed it embedded in the dust clouds are huge girders and entire sections of steel framing that are being hurled out of the building the horizontal speed of some of the girders has been cocked over seventy mph some of these girders impaled themselves in the sides of neighboring buildings some landed as much as two football fields away from the base of the tower what could hurl heavy girders with such force and given such speed some people have suggested that the weight of the tower crashing down on the girders caused them to flex and they sprung sideways by a spring action but we are not seeing isolated jumping girders we're seeing a major fraction of the mass of the building steel concrete office furniture and the remains of human beings reduced to small pieces of rubble and fine dust and be explosively ejected in all directions bone fragments or falun on the roofs of the chasing buildings the bones were not crushed in the falling mouse or they would have been trapped in the debris pile they were pulverized along with everything else and blown out in all directions the nist investigators have claimed that the top section of the building above the plane impact point came down like a pile driver crushing the undamaged lower section of the building all the way to the ground the top section of the building is however noticeably a there is nothing above the ring of explosions except for a fountain of debris can you see a pile driver that does not appear that the building is being crushed by anything the waves of destruction and explosive ejections of material are occurring over a wide zone that continues all the way to the top of what remains of the building the scientists at nist did not model the collapse of the towers their analysis was gravely flawed in many ways but the biggest flaw was that the scope of their investigation was artificially limited they took their analysis only to the point of initiation of collapse as though all that followed was inevitable and needed no explanation the scope of their investigation was artificially limited to what might have happened or could have happened to begin the collapse what they explicitly did not take into account is what actually happened by limiting their investigation to the natural precursors of collapse plane damage in the fire they ruled out from the start any possibility of discovering evidence of planned demolition in other words anything that occurred during the collapse itself such as the evidence you're seeing here was explicitly scripted out of the investigation any analytical model of the collapse no matter how simple or how sophisticated is a bad model and bad science if it does not come back full circle to explain the actual observations what  the first video that we looked out was building one of the world trade center complex also known as the north tower it's identifiable as the one that has the antenna on top of the roof building to look very much life except it didn't have the antenna and there was a third building that completely and totally was demolished on september eleventh which is building seven this was this there are seven buildings in the world trade center complex all the buildings were demolished to one extent or another but buildings one two and seven were completely demolished into disassociated materials that landed well in the case of buildings one and two it was spread all over the place but in the case of building seven it was a nice tidy pile right in it's own footprint this building is it would basically cover a football field it's one hundred meters wide and it's forty seven stories tall so it was about it's close to half the height of the world trade center towers and it was a huge building it was not hit by an aircraft and it was it dropped at five twenty in the evening and it just  was a sudden onset and it was a very unusual collapse people who look at this building for the first time frequently this is all it takes to realize something very fishy is going on here it looks like a controlled demolition so what i'm doing in this next video is taking measurements of the roof line as it comes down i have heard various people say that the building was coming down close to free fall i wanted to get the measurement myself i teach physics and one of the tools i use in the classroom is an analysis tool of enables you to take a video clip and put markers on the training and then as long as you have something in the picture that you know the size so you can calibrate the measurement you can actually get the data from the little marks you put on it and use this to calculate things like velocities and exhilaration and so forth so this  was one of the key measurements i did fairly early on and fact the one i'm going to show you it says it's a revised version i did an earlier version before this one this particular video was made in august of two thousand and eight at the time that nist the national institute for standards and technology released their building seven analysis and they gave data in there that allowed me to get a good calibration and so this is the result of that measurement this is a revised analysis of the downward acceleration of the world trade center building seven which collapsed in a manner suggestive of controlled demolition on september eleventh two thousand and one by earlier analysis which was posted on you tube under my own it was based on the best information i had at the time but now i've been able to improve on my results using new information available in the recently released nist final report on building seven despite the accurate data available to nist their final report makes dishonest claims about the rate of fall of the building i'll come back to the nist report at the end of this video in my earlier video analysis i use the width of the building which is known to be one hundred meters to calibrate the scale of the image in this remake i have used the vertical spacing of the windows visible as horizontal streaks on the face of the building from this i was able to identify the twenty ninth floor which is listed in the nist document as having a height of six hundred eighty three feet six inches measuring from some baseline which they don't specify they have the blueprints i don't but i take this measurement to be reliable other measurement they give is the height of the roof lin which they state is nine hundred twenty five feet four inches above their baseline the difference of these two heights converge of the meters is the basis for the calibration of this video the actual measurements were done exactly as before the cursor was placed on the corner of the building and marks were placed frame by frame the built in functions of the physics toolkit software capture the positions and times of these marks in a data table from which it computes and displays various kinds of graphs i'm here plotting velocity as a function of time the slope of this kind of graph gives the acceleration notice that the data hovers close to zero for nearly a second and then it drops precipitously from the moment of the drop the slope of the line appears essentially constant for about two and a half seconds by marking two data points the program can compute the best straight line to fit the data for the linear portion of the graph the slope of the line is the acceleration down here at the bottom of the computer to acceleration is shown minus nine point eight eight five meters per second squared the minus sign indicates downward acceleration acceleration of gravity from new york city is nine point eight zero two meters per second the measured acceleration is within one percent of the acceleration of gravity given the graininess and size of the image one percent is not a significant difference from the actual acceleration of gravity so the most accurate way to characterize the result to say acceleration of the building is indistinguishable from freefall notice that a little after the three second mark on our graph about two and a half seconds after the building drops the acceleration ceases to be uniform this indicates the falling building is starting to encounter more resistance any measurement of the average acceleration that continues for more than the first two and a half seconds of fall will show a lower average acceleration masking the fact that for a significant two and a half seconds building was in literal freefall freefall can only be achieved if there is zero resistance to the motion in other words the gravitational potential energy of the building is not available to crush or deform anything during all of the gravitational potential energy of the building is being converted into kinetic energy and nothing else any breaking bending crushing or pulverizing of the building components is occurring without the assistance of the free falling portion of the building any force the top portion of the building might exert on the lower portion would be reflected in a reaction force that would produce an observable slowing of the rate of fall or reaction force is observable in this graph only in the last seconds when the velocity strays from the straight line let's return to the nist final report on w t c seven i would like to clarify one thing right away on page forty there is a phrase quote assuming that the descent speed was approximately constant unquote is sumption is clearly falls from even casual observation however the fact that they proceed to use a formula for constant acceleration clearly indicates the constant speed reference is a misstatement or actually assuming constant acceleration more bizarre is the claim that quote the actual time for the upper eighteen stories to collapse based on video evidence was approximately forty percent longer than the computed freefall time if you start with a forty percent increase in the time of fall and work backwards to compute the effective acceleration their claim is equivalent to saying acceleration of the building is only five meters per second squared which is fifty one percent the acceleration of gravity our results however clearly show a significant stretch of time in which the celebration of the building is indistinguishable from the acceleration of gravity itself in other words complete freefall they did not use a method that sampled the position vs time to show the velocity profile as was done here the nist report uses only two data points i suppose a start of the collapse and the time the roof line disappears from view by choosing an early starting time several seconds prior to the onset of freefall and computing only the average acceleration between that point and the disappearance of the roof line they gloss over everything that happened in between i'm sure they detected some movement of the replying at the point where they started the clock as a rationale for choosing that point even our data here shows a tiny amount of motion in the first second but what was going on during this time is qualitatively different from what happened moments later the event triggering the start of their measurement could more accurately be described as precursor movement this is like timing the acceleration of a car in a drag race where the starting light goes on then the driver revs his engine a few times before letting out the clutch it may be a fair way to penalize a sloppy driver but it doesn't say anything about the acceleration of the car once  is actually moving this method tells us nothing about the nature of the motion itself they merely assume uniform acceleration over a time interval in which it is clear that the acceleration is not uniform mislabeling the assumption to be constant speed indicates sloppy work but asserting uniform acceleration for an interval where the building sits nearly motionless for several seconds and drops for several seconds in freefall is beyond incompetence it is a crude blatant lie the average acceleration is a meaningless quantity it is the instantaneous acceleration that is significant because the acceleration at any moment is an indication of the forces at work to measure and publish meaningless average acceleration when sufficient data any multi million dollar budget are available to measure the actual velocity profile constitutes either gross incompetence or an attempt to obfuscate the issue this is high school physics we're talking about if they can't get the high school physics right what confidence can we have in there multicolored computer animated whiz bang simulations to tell us the exact sequence of girder failures without any physical evidence for any of it i'm a high school teacher i teach my students better lab practice than this demonstrates here in this video i have measured the philosophy profile and the instantaneous acceleration of the building with orders of magnitude better precision than this and i did it was a zero budget free software tool commonly used in high school physics classes and a copy of a video downloaded from the internet i know the guys at nist are not incompetent but i'm left to conclude is that their only purpose in even mentioning freefall is to muddy the water and the discussion the rate of fall of the building is an embarrassment to the official fairy freefall is a small detail in the whole complex analysis but it is not a minor issue buildings cannot fall at freefall through themselves because even a weakened building requires energy to break up the pieces crush the concrete and push things around in the following building pushes things the fall is not free the things push back and the reaction forces will measurably slow the descent of the building this is why one would reasonably expect crumbling structures to come down in a tumbling halting irregular manner in short the evidence is clear we are witnessing not the collapse of a building when nist released their report on building seven in august of two thousand and eight one of the things they did was to have a technical briefing and at first i thought well no way am i going to be accepted to give  to ask questions at this briefing because it was limited to engineers or scientists with institutional affiliations of some kind but i want to head and i applied anyway and guess what i was given the password and just five minutes before the briefing started i was unable to submit a question which i did so this video coming here is shows a little bit of what happened at that briefing in august two thousand and eight after a seven year delay nist the government agency charged with investigating the world trade center collapse was released the draft of their final report on the collapse of world trade center building seven for public comment in that report they claim that the time for the building to fall the first eighteen stories that's the part of the collapse visible on many videos was forty percent longer than it would have taken had been in freefall i responded with a video posted on you tube called w t c seven in freefall in which i showed there for approximately two and a half seconds building seven fell at a rate indistinguishable from fr furthermore in that video i showed that in this three methods ology was not a valid way to analyze the true motion of the building and this measurement was not just wrong it was fraudulent that on august twenty sixth miss technical briefing and which engineers and others with technical credentials could pose questions i'm a high school physics teacher so i figured i would be excluded however i went ahead and registered citing my membership in the american association of physics teachers as my professional affiliation by the way i am not speaking for a p t that was just my passport into the briefing to my surprise my credentials were accepted and i was able to pose a question here's a little of how it went our next question comes from david shambler the american association of physics teachers any number of competent measurements using a variety of methods indicate the northwest corner of w t c seven fell w exhilaration within a few percent of the acceleration of gravity yet you report contradicts this claim in forty percent slower than freefall based on a single data point how can such a publicly visible easily measurable bothered to open the book but this is nist speaking so let's continue the the analysis show there's a difference in time between a freefall time a freefall time would be an object that has no structural components below it and if you look at the analysis of the video it shows that the time it takes for the seventeen for the roof line of the video today to collapse down the seven hundred floors that you can actually see in the video below which you can see anything in the video is about three point nine seconds what the analysis shows and the structural analysis shows the collapse analysis shows it's that same time that it took for the structural model to come down from the roof line all the way for the seventeen floors to disappear is five point four seconds it's by one point five seconds or roughly forty percent more time for that freefall t happen and that is not at all unusual because there was a structural resistance that was provided in this particular case and you had you know you had a sequence of structural failures that had to take place and where everything was not instantaneous saying is freefall for the eighteen stories under consideration would have taken three point nine seconds however their computer model simulating collapse required five point four seconds  slower collapse time was to be expected since there was structure supporting the building as it fell slowing the fall but there was a progression of failures that had to take place and that these were not instantaneous all of this makes sense as long as you don't look at the evidence the evidence shows that freefall actually occurred but since their computer modeling could not come up with a scenario that would allow for free fall they had to declare freefall out of bounds and try to cover up the evidence the problem is unlike the columns and girders buried deep inside the building the motion of the building is right out in plain view since their model predicted five point four seconds for the eighteen story collapse they do to flee conjured up a five point four second measurement to match they had to stretch themselves to do it but they did it they found the disappearance time and they went out of their way to pick an artificially early start time exactly five point so the question is why did mr assume that the descent speed was approximately constant stephen jones was calling attention to the obviously iranians claim on page forty of the draft report that stated that the building to stand at a constant speed frame search of the of the time so that was down to one thirtieth of a second and then we did the same thing for when the top of the parapet disappeared and we found that for that time to be five point four university he taught engineering at the university of colorado in boulder has a long resume on top of that don't you think he probably knows the difference between speed and acceleration don't you think he could explain it with perfect clarity if he wasn't so preoccupied trying to cover his tracks don't you find it interesting that the five point four seconds he measured for the collapse time just happens to exactly match the theoretical prediction of their model that kind of precision is incredibly rare when modeling real world events incredible is the right word it's not credible this measurement has all the characteristics of what we call dry lobbying manipulating the data to fit a predetermined outcome it's an ethics violation and science on a par with plagiarism any engineers engaging in this kind of sleight of hand should lose their licenses the larger implication of course is dry lobbying in this kind of investigation would constitute a criminal cover up after another round of quibbling someone had to step in and bail out porch on any verify that i think it's something that we need to carry  that was august this is november the final version of the mist w t c seven report just came out and guess what we have a revised analysis of the building collapse rate constant speed as our constant acceleration is out instead we have three phases of collapse with a whopping two point two five seconds of absolute freefall irrelevant five point four seconds is still defended in the wording but plays no apparent role other than c y a for john gross and associates so free fall is hereby official dogma how are they going to handle all the ramifications of that inconvenient fact read on it says the three stages of collapse progression described above are consistent with the results of the global collapse analysis discussed in chapter twelve mists and sistar one dash nine that's it freefall went from an  impossibility the required back flips and logic to obfuscate to a simple fact to be measured then declared consistent with their fire induced collapse hypothesis apparently they have now decided that free fall is ok as long as it is seen as a part of a longer stretch of time the covers the required five point four seconds in other words they drop the bullying tactic of blowing smoke to obscure the facts and adopted an alternate bullying tactic cover it with a lie and walk away however nist cannot walk away from freefall now that nist has certified freefall as fact take a look at the implications for those of you who don't have a lot of physics background one of the concepts that might be a little bit tricky to understand is the difference between constant speed and constant acceleration select elaborate on that just a little bit  r constant speed as if you were look at the speedometer in your car and it's holding steady so if you're going down the freeway at sixty miles an hour that's constant speed in the case of gravity if i drop something it's accelerating the thing that you drop is going to accelerate because it starts off at rest and then as time goes by it's going to pick up equal increments of speed in equal amounts of time so in the first second it picks up a little speed in the next second it picks up another equal amount of speed and so forth and out of that's what we mean by acceleration so excel aeration is the rate of change of speed just like speed is the rate of change of position so these are related quantities but they're very distinctly different interesting to note that even just had some trouble with that concept so don't feel bad i was originally going to make a two part series on the their measurement like they got an iranian measurement from which they could claim that it took forty percent longer than freefall even though it's obvious just looking at it that it's close to freefall and with a measurement you can see it's pretty much right at freefall so how do they do this i'm just going to let this video speak for itself this is how i tracked down the way nist did that measurement part two of the series was going to be an exploration of the significance of this admission the world trade center building seven underwent a period of freefall acceleration that will have to wait for part three after suggesting in part one of this video that john gross is method for determining the time of fall might constitute dry lapping in other words falsifying measurements to support a pre determined outcome i got curious to know exactly what event he picked to start the clock the measurement is a little tedious  result is very significant that's often the way it is in science so stay with me on this one let's start with john gross explanation of how he determined the time of fall by the way you might recall this was not the question he was asked but it is the answer he gave our calculation was based on the amount of time on the top of the parapet to fall till he disappeared from view between the two buildings seen in find the point he picked as the start of collapse we have to work backward the ending point of this measurement was when the roof line came down to the level of the twenty ninth floor in our video there's a structure on the roof of the foreground building that lines up with the twenty ninth floor of building seven so it's easy to identify the import of the video into a measurement program called video point which has a frame counter and step forward to the frame where the roof line lines up with the foreground marker that's frame one seventy eight counting from the first frame of the video clip on using at thirty frames per second five point four seconds comes out to be one hundred sixty two frames subtracting this from frame one seventy eight brings us to frame sixteen so let's go back and see what's happening at or about frame of sixteen i put a red mark on frame sixteen so as it goes by you'll recognize it let's go back to the beginning and step through this section of the video watch for the beginning of the collapse one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty twenty one twenty two twenty three twenty four twenty five twenty six twenty seven twenty eight twenty nine thirty we're up to frame thirty did you see the collapse begin i didn't try rewinding the video a few times it's pretty boring there's not the slightest hint of any collapse until frame forty forty forty one forty two forty three forty four forty five forty six forty seven forty eight forty nine fifty two one fifty two fifty three fifty four fifty five fifty six fifty seven fifty eight fifty nine sixty sixty one sixty sixty three sixty four sixty five sixty six sixty seven sixty eight sixty nine seventy there's a tiny motion of the corner of the west penthouse at frame forty and there is no more motion and tell about frame forty six note that the motion of the penthouse precedes the movement of the roof line there is no measurable movement of the roof line until frame forty six that's a full second beyond frame sixteen even then there isn't any progressive ongoing movement of the roof line until about frame sixty by then we're back to just over three point nine seconds of collapse time or in other words the onset of freefall the only rationale i can see for choosing frame sixteen to start the clock is to make the measurement come out to exactly five point four seconds to agree with prediction of miss collapse model but what if i'm wrong but if they did see some tiny movement on a clearer version of the video that tiny movement whatever it might have been did not last it would have had to have been a glitch and the scientists at nist would recognize it as a glitch because there is no measurable difference in the height of the roof line for the next twenty to thirty frames what can we conclude you can draw your own conclusions but i think it's pretty clear that the whole idea there was any kind of real five point four second collapse interval is a fiction it's a crude fabrication and the three stage collapse sequence is pseudo science in the service of an ongoing cover up in part three we will return to the central question in conceding freefall what has nist actually admitted the measurement i did in part two of this video is how i actually determine when the start time was however is not very graphically appealing i thought what i did later was i added a clock to the video sequence i actually selected out just those five point four seconds by themselves and i did a separate run just so that you can actually see what this timing really looked like so let's watch that now in part two of the video series w t c seven missed finally admits freefall i look at mists claim the building seven took five point four seconds for the top of the roof line to descend to the level of the twenty ninth floor i wanted to address the question what was going on when th team started their clock the answer not much the video i created at the time showed my actual process of discovery i stepped through the video and counted frames i have since created a more graphic illustration of the famous five point four second interval this time i've added a clock to the frames each full cycle marks one second here is the five point four second here it is again in slow motion notice that the building doesn't start falling right away how about now maybe now the clock was started a second and a half before the corner of the building started to move in about a second prior to any noticeable movement of the penthouse there is nothing subtle here this is the measurement nist use to compare to claims that the building came down at free fall whatever they might claim was happening at their starting point it had nothing to do with the rate of fall of the building ok part three of the series actually is what i was intending to do as part two this is going to spell out the implications of this admission that building seven went through a period of freefa shyam sunder is the lead investigator for the nist analysis of the collapse of world trade center building seven in a technical briefing on august twenty sixth dr sooner clearly explain why freefall for trade center seven was impossible as a difference in time between a freefall time of freefall time would be an object that has no structural components below it and that is not at all unusual because there was a structural resistance that was provided in this particular case and you had yet a sequence of structural failures that had to take place now everything was not instantaneous this brings us to their computer model and this so called investigation actually consists of finding a way to reproduce the mysterious collapse of the building using a computer model is sumption is that if the computer model can be made to reproduce the observed collapse pattern that must be how it happened the problem is if something unexpected was going on like explosives for instance you're not going to discover it in the computer model for that you need to look at the actual evidence so why not examine the steel directly oh yes there isn't any at least there isn't any after it was hauled away to asia and melted down and this investigation has been compared to conducting an autopsy without the corpse as of two thousand and five nist reported having only two hundred thirty six pieces of steel from the world trade center complex none of them unambiguously identified as being from world trade center seven we've all watched c s i anyone serious about solving a crime knows the importance of physical evidence yet here the crime scene was scrubbed the evidence was destroyed and the investigation was delayed for years destroying a crime scene is itself a criminal act destroying the steel has absolutely no justification except to cover up the cause of the collapse so even if we knew nothing else about the events of that day we can see immediately there was a cover up knowing there was a cover up is a strong indication there was a crime someone wanted covered up any investigation that does not acknowledge this basic fact is not really an investigation it's an extension of the cover up this claims their computer model can account for the observed phenomena so let's look at nist model except we can't the software they use to do the modeling is available but their model actually consists of all the numbers and measurements and assumptions together with any tweaks to the system they might have used to get it to come out the way they wanted if that information were released their results could be checked by anyone with the appropriate skills and software tools but nist has not released the numbers all we've been shown are some of the selected animated outputs they were able to get their model to produce is their model realistic we don't know some models are chaotic in the mathematical sense in other words tiny variations in the inputs might result in wildly different outcomes is nist model stable or chaotic realistic or contrived honest or fraudulent we don't know we can't know without independent testing the very process of running the model until it produces the kind of result you're looking for is called selection bias if you think about it this methodology is explicitly based on a selection bias even if you could show what might have happened it doesn't show what actually did happen the very fact that nist has not released their model strongly suggests they don't want their results checked in other words their results are intended to be taken strictly on faith if nist has not released their modeling data and the really not release the report and the fact that this is their final report indicates they do not intend to do so therefore on the face of it their report is little more than a fancy expensive cover up one fact we do know about in this model is it does not allow for free fall the best they could do is five point four seconds for the building to crumple down through eighteen floors crumpling absorbs energy and that makes freefall impossible there is nothing in the models we have been shown that even resemble a three stage collapse with a freefall component after all shyam sunder put it himself free fall happens only when there are no structural components below the falling section of the building any natural scenario is going to involve a progression of failures and these don't happen instantaneously so in the end we come back to where we were in the beginning on first impression we were looking at a classic controlled demolition  claim to found a way it could have happened naturally but in fact they failed the only way they can support their claim is through lies secrecy and pompous but false pronouncements that constitutes a failed agenda explosive demolition is the only scenario that has been put forward that could actually account for the observations where does that leave us we have a building that underwent directly observable and now officially acknowledged freefall with no plausible mechanisms other they an explosive demolition we have an official investigation by a government agency that has fraudulent william manipulated data has refused to even consider existing physical evidence that explosives were used wrapped themselves and their data in secrecy and offered up pronouncements as conclusions to be taken on faith the nist investigation is a fraud and a farce we need a new fully empowered truly independent and investigation we are told that the twin towers of the world trade center were weakened by airplane impacts and fire then came down in a gravity driven collapse just look at the suppose of collapses it stretches credibility to even call them collapses these events resemble explosions even eruptions more than collapses we're not seeing the walls come tumbling down with the dust blown out to the side we are seeing nassif projectiles thrown hundreds of feet by massive i mean multiple tons a single perimeter wall unit consisting of three fourteen inch square columns thirty six feet long connected by spandrels weighed on the order of four t some of these are seen flying outside the debris cloud reaching farther than the majority of the debris my very first personal investigation of the nine eleven the events was when i watched the expanding debris cloud from the north tower on a d v d several years ago i paused the d v d took out a ruler and estimated the horizontal velocity of one of the debris streamers right on the television screen my rough estimate was about sixty miles per hour without measurement i was hooked i realized something very strange was going on i followed up with digital measurements on videos downloaded from the internet using a tool i had available of the time physics talk of some of my early measurements using low resolution videos were crude over time i have gained access to higher quality videos and better measurement tools so i decided to go back and redo my earlier measurements of projectile speeds first i looked at the westward moving projectile from the north i had crudely measured on the television screen few years ago this time i got a reliable value of twenty five meters per second which translates to about fifty six miles per hour my original estimate was pretty close on a video of the south tower i noticed a large a long gated object moving like a javelin above the main debris cloud on the original video or i saw this object the camera was zooming the whole time which made the measurement difficult i recently found another video which shows the same projectile but taken with a stationary camera result twenty meters per second forty five mph another high speed projectile was launched northward from the north tower late in the collapse toward building seven close up show the structure of the object which appears to be one or more wall eunice this particular video footage was shot by rick siegel from across the hudson river  camera a lot so the measurement was a challenge but i do compose the video into individual images and manually align the images to stabilize the video or use the stabilized video to do the measurements and got good uniform results thirty five meters per second or seventy eight miles per hour i repeated this measurement with other techniques and i've consistently gotten results well over seventy miles per hour high speed massive horizontal projectiles may not be smoking gun evidence all by itself but it is a very suggestive of an explosive event it's another piece of the puzzle building seven as i measured as we talked about already came down at free fall on ours at the acceleration of gravity when i started measuring the north tower came straight down or pretty much straight down and so it's easy to measure it as well but i measured the roofline of the north tower it did not come down in freefall it came down close to two thirds of its point six four six or sixty four percent of freefall but in any case  side did the measurement my first reaction was all well it's not freefall and i set it aside but i came back to it later and i asked myself the question how long how much for how much kind of force is needed to slow it down so that it excel orating downward but at less than gravity and so i did the analysis using standard techniques that i do for you know that when any body sets up a physics problem it's like taking the body that you're looking at in isolating it from its surroundings and apply all the forces to this thing called a free body diagram and once i did that i came up with a surprising result i wasn't anticipating this but it actually is a very solid  proof that the top section of this building was not what was causing the bottom section to collapse so let's watch the video and i'll have more to say it afterwards this is the start of the collapse of world trade center number one also known as the north tower we are here tracking the motion of the roof line at two tenths second intervals through approximately thirty two meters or eight stories this graph shows the height of the roof line as a function of time in alice sosa's simpler if we plot velocity as a function of time on this kind of a graph a straight line indicates constant acceleration first note that there is a sudden onset of collapse as the point we are tracking makes a sudden transition from being at rest to approximately constant downward acceleration the slope of the graph indicates that the acceleration is six point three one meters per second squared downward which is sixty four percent of freefall in other words once it starts falling the upward resistive force is only thirty six percent of the weight of the falling section of the building so far so good but now turn it around newton's third law says interactions between objects work both ways the forces two objects exert on each other are always equal and opposite if the upward force acting on the falling blog is thirty six percent of the weight of the falling block the downward force exerted by the falling block must be exactly the same thirty six percent of the weight of the falling block in other words the top section of the building is exerting less force on the lower stronger undamaged structure then it would if it were simply sitting motionless therefore as long as the top section of the building is in uniform downward acceleration it cannot possibly be providing sufficient force to destroy the building this may seem counterintuitive to you you might think a falling block coming down on the lower section of the building would exert a greater force than a stationary block but that is true only if the falling block actually impacts the lower block which would cause the falling block to be celery the only way the falling block can continue to accelerate smoothly as we see here is for the lower section of the building to give way without significant resistance if this rate of acceleration continued all the way to the ground the building would fall in about eleven point five seconds this is close to the observed collapse time so far i've been using the term block loosely what we actually see here is the following section of the building turning to dust before our eyes but what is happening to the upper section of the building behind the dust clouds doesn't really affect this analysis given the fact that it is accelerating downward the top section of the building whatever its condition cannot possibly be destroying the lower section of the building the destruction of the building must be caused by something else this d v d has focused very much on the physics of nine eleven and basically it's a personal on statement on my part this is the angle i come at it because this is who i am and this is what i know and one of the things that amazes me is how i as simply a high school teacher have enough if i actually apply what i know there are so many things that are so clear about what's happening there's so many people out there i've talked to that are there much more knowledgeable about science either than even than i am and the typical result is they've never even heard the building seven came down they've never bothered to look at the evidence and it's like there's there's a very strong stigma that has officially been placed on this to call it conspiracy theory and to try to stigmatize any any interest in these events nine eleven really is an event that changed the world and it's changed everything since then it hasn't changed our fundamental values but it's changed the way our government interacts with the people we have the ongoing wars of nine eleven as some people have put it and as long as those wars are continuing to be fought there we can't just let nine eleven get swept under the rug because this is where these things come from we've killed over a million people in iraq that's a statistic that the papers don't tell you but it's been researched multiple times by reliable institutions we have killed over a million people in iraq it's not just that they have killed each other  this is an atrocity on our huge scale and this is something that we cannot just let go there's so many angles to this i've come out of from the point of view of science there's the political science there's the sociology there's the question of how come official science like the people involved with nist have been manipulated the way they have to take good scientists with integrity and be able to use their talents and stamp it with a political agenda and how this how people can allow this to happen with their life's work who am i speaking to i'm speaking to the general public whoever house anough interest in these events to have watched this video through but i'm also speaking to people how backgrounds in science that if you actually look and ask the questions the kinds of things i've done or if you have expertise in other areas look into this from your own particular particular perspective i specifically am encouraging people who are involved in official authoritative science such as this to evaluate your life's work daniel ellsberg as an example of someone who found it necessary to step outside the norms of what was expected of him in order to have a life that he could he could live with himself and i i really am hoping that some of you who are perhaps watching this video if you have knowledge of what really happened on that you will make yourselves known and share this with the world this is something that has not been resolved yes it's a few years ago but the wars of nine eleven  continuing and it can't just be swept under the rug it's too important for that we need nine eleven tru