We previously saw a Fox News pie chart that had a couple extra slices (here). Now, fair and balanced math adds up to 120 percent of voters indicating that they view the science on global warming to be rigged.
This is an interesting Rasmussen poll when you add up the number and discover that you are in a parallel universe.
The question is: “In order to support their own theories and beliefs about global warming, how likely is it that some scientists have falsified research data?” According to the poll, 35 percent thought it very likely, 24 percent somewhat likely, 21 percent not very likely, and 5 percent not likely at all (15 percent weren’t sure).
This rather dubious poll is offered to show that people are dubious about the science and math of global warming experts.
For the full story, click here
I think that once the buildings came down it was a partially isolated system as you had 5 sides of solid concrete around and below the debris. As you all know your basement has a fairly constant temperature. So I think Slarti’s contention of a closed system is not that far out of line. It certainly wasn’t a 100% open system because of the constraints given by the foundation and surrounding soil.
Buddha,
You said:
“Got to go with Bob on that one. Astronomical impact events are a totally different creature than a building collapse.”
No, both of these events are inelastic collisions. If we exclude the quantum mechanical and relativistic realms (i.e. consider Newtonian mechanics valid), then the laws of physics are the same at every scale. The laws of physics (well, actually they’re the laws of the universe, physics just figured out what some of them are ;-)) determine what the change in kinetic energy in an inelastic collision is. An impactor striking the earth does not bounce, therefore it is an example of an inelastic collision – the calculations would be exactly the same (although the fraction of the KE required to destroy the structure of the meteor is much smaller). The WTC collapse was also an inelastic collision – the rubble didn’t bounce. More accurately, it was many individual inelastic (and some elastic) collisions which I’m treating in aggregate. I do this according to the same principle that lets us calculate the gravitation effect of the earth as a whole rather than each individual molecule individually and recognizing that the rubble as a whole had a quantifiable amount of kinetic energy which, after a collision in which the rubble (taken as a whole) did not bounce, was no longer there. While it can be argued that this was not an inelastic collision, I’m on solid ground here, assuming that I’m the assumption that the collision is inelastic is a reasonable one to make, my analysis is unassailable (provided one understands the physics I have described). The purpose of the calculation that I made was to determine how much energy was involved in the WTC collapse and get a ballpark idea of how much heat was generated by impact ASSUMING that the collapse was unassisted by additional explosives. The point of doing this was to provide a scientific basis for judging if the impact-fire theory is capable of explaining the observed heat at ground zero*. Within that context, the assumptions I’ve made are entirely reasonable. I’ve been doing these sorts of calculations since an astrophysics course my junior year (within one order of magnitude was considered exact, within two was acceptable) and its often surprising just how accurate these calculations turn out to be. On the whole, conservation of energy demands that we account for all of the 1 trillion joules of gravitational potential energy contained in the WTC. I’ve done that. I’ve accounted for kinetic energy, seismic energy, sonic energy, energy to destroy the structure of the buildings (even though this remains as heat) and generate the pyroclastic flow, and thermal energy. I did not account for the gravitational potential energy of the rubble heap (on the assumption that GPE rubble << GPE WTC). No other destinations for the energy involved have been suggested. I stand by my analysis.
*The only evidence I've seen for POOLS of molten metal, is a picture of workers clustered around a glow. Since one of the workers was standing in the light of this glow and his legs were not on fire, I don't give it a whole lot of credibility. I think there is a big difference between blobs of molten iron dripping down a beam and pools of molten metal.
Buddha said:
"For one, you are talking about differences in KE that are off by huge orders of magnitude even if you discount the differences that would occur due to angular momentum."
Yes, they are events of vastly different scales, which is why one created a crater 180km in diameter instantly liquifying 25,000 square kilometers of rock and killed off the dinosaurs and one merely melted some metal. They are both inelastic collisions. I'm not sure what angular momentum you're talking about.
Buddha said:
"Asteroids and comets move A LOT faster than planes do. There is also the disparity in average mass issue. Many meteors are small. Some are as big as mountains. Some are as big as states. Big ones. Not Rhode Island. That makes it apples and oranges too. Had they flown the jets in a parabolic arc and dropped into the towers nose to roof or at a steeper angle? It might be a more appropriate analogy but even then it wouldn't be exact or particularly helpful since even the Vomit Comet maneuver wouldn't impart enough KE to makes those differences in scale negligible."
My energy analysis was not of the plane strikes, but of the building collapses, but the plane strikes are inelastic collisions as well (the planes don't bounce). Although, for various reasons, this is a more difficult collision to model, the end result is that the planes had a large amount of kinetic energy the instant before the crash and a short time later it was gone. Angles of attack and relative speeds are irrelevant – there was kinetic energy and after a collision which didn't include bouncing, it was gone. I'm justified in applying the physics that govern these types of collisions.
Robert said:
“Another major flaw is the complete disregard for impact angle. What are the chances that most of the falling material hit the material at the bottom (earth and rubble) at a 90 degree angle (the angle most efficient for energy transfer), and why/how did it convert to thermal energy?”
Did the rubble bounce? If not, I correctly applied the physics of inelastic collisions. Trying to sound like you know what you’re talking about by saying things like ‘the angle most efficient for energy transfer’ is cute. Prove it. I have provided extensive explanation and example of kinetic energy being converted into thermal energy and will add another substantial post shortly.
You all might want to check into the Charpy impact test. This measures the energy a piece of steel is able to absorb.
There is also something called “carbon embrittlement” of steel which may or may not have any bearing on the discussion. If it did, it would be at the floors impacted by the fires.
Also Robert should be aware of the problems with Nuclear Waste canisters and thermal embrittlement of low alloy steels, which I assume the WTC was constructed of.
So the connections may have a reduced ability to resist fracture under elevated temperatures at the floors the planes hit.
There are not only Newtonian mechanics at work in this collapse. Chemistry (other than thermite) and material science are also playing a role.
Bob,
Go back to school.
You said:
“You’re now forced to account for the Work creating heat”
I’m not in violation of the law of conservation of energy, you are. You don’t ‘create heat’ by ‘doing work’, you obtain heat by converting it from other forms (e.g. when you lie in the sun electromagnetic energy is converted into thermal energy – there’s also quite a bit of DNA damage, so wear sunscreen).
Robert: “The major flaw in Slarti’s conclusion is that he considers this to be an isolated system, which causes his calculations to ignore all interactions with the environment (interaction with the environment is scientifically impossible in an isolated system).”
Yes, but he’s doing so only as part of his hypothetical. We know the event is not an isolated system, and we know it’s not even a closed system since, I argue, you have to account for the lack of thermal equilibrium; i.e. the failure of the rubble to cool down to surrounding temperature. It is technically an open system as soon as so much as the sound echoes out in all directions.
Robert: “The pulverizing of cement into rubble expends a lot of energy in the form of work. The ejection of metal girders 600 ft expends a lot of energy in the form of work.”
No argument here. And once the Pe is used to do work, it can’t be used again to create pure Ke and then heat. You’re now forced to account for the Work creating heat; which is another reason his meteor analogy falls short.
Robert: “Another major flaw is the complete disregard for impact angle. What are the chances that most of the falling material hit the material at the bottom (earth and rubble) at a 90 degree angle (the angle most efficient for energy transfer), and why/how did it convert to thermal energy?”
Even more troublesome is begging the question that buildings are capable of collapsing at near free-fall speed without any ‘help.’
Robert: “Why didn’t it perform work by moving earth or rubble? Slarti assumes that all of it hit at a 90 degree angle, and most of the energy was retained in the rubble instead of being dispersed into the surrounding earth.”
It’s the free lunch problem; the problem is begging the question of the work required to create rubble in order to hypothesize about this ‘extra energy’ available to make such an impact.
Robert: “The majority of energy left in the falling material was transferred into the earth.”
That’s a fair statement.
Robert: “Early realization that this is not an isolated system would have made that easier to acknowledge.”
True enough. Then again, in the interest of argumentation, you have to give him room to make his point. However, to content or imply that the thought experiment is as good as an explanation as to what happened per the actual conditions of the event, i.e. which are incomparable to the conditions of the thought experiment, is simply unacceptable.
Robert,
I suggest you get working on your test.
Robert,
The analysis you linked is far less sophisticated than what I have done here (although it is done along the same lines). It also leaves you with half a trillion joules of heat in the basement. Ouch.
Slartibartfast,
“The answer to my previous question: “Go watch a building being brought down by controlled demolition. Where does the energy to destroy the building’s structure come from?” [it]is gravitational potential energy.”
Then how was it that the building was standing prior to the event? The GPE has been there since the building was completed, but it didn’t fall. The opposing force (the structural support) was removed. That’s why it falls. If you remove enough of the structural support (take away resistance) and it will free fall.
Robert said:
“Each floor required 14 billion joules of energy to break it loose.”
Show your work.
Robert,
Re: high school physics test link
I’ve shown you how to use the difference between collapse time a free fall time to estimate the energy available for demolishing the building. Your test is to use the times given in your link (9.2s free-fall vs. 10-13s collapse – the values I used were 6s vs. 6.6s*) to determine this available energy. Good luck! You may start working… now.
*obviously the numbers that I used were from the WTC7 collapse, not one of the twin tower collapses. Bob, I am now estimating that 82.6% of the GPE of WTC7 went into thermal energy – you’re welcome. The calculations for WTC1 and WTC2 are still valid, and I’m sure Robert will tell us what the exact numbers are shortly. 😉
Slartibartfast,
Each floor required 14 billion joules of energy to break it loose.
Robert said:
“Other than the fact that the buildings did hit the ground, what did you use to calculate the amount of energy required to break the floors loose, and pulverize the concrete? You math simply states that this is the amount of energy that was used, not that is it the amount of energy that SHOULD HAVE been required to make it happen. Your stating what it did take, but ignore what it should have taken.”
I said that 100 billion joules (24 metric tons of TNT) was available to destroy the structure of the building. If you are suggesting this was not sufficient, show evidence. The answer to my previous question: “Go watch a building being brought down by controlled demolition. Where does the energy to destroy the building’s structure come from?” is gravitational potential energy. The twin towers (being more that 4 times taller than any building brought down by controlled demolition) had a lot more GPE that you see in any CD.
http://9eleven.info/HSPhysics.html
Slartibartfast,
Other than the fact that the buildings did hit the ground, what did you use to calculate the amount of energy required to break the floors loose, and pulverize the concrete? You math simply states that this is the amount of energy that was used, not that is it the amount of energy that SHOULD HAVE been required to make it happen. Your stating what it did take, but ignore what it should have taken.
Incidentally, 100 billion joules is the equivalent of 24 metric tons of TNT. If you need significantly more energy for your theory, please explain how 50 tons of explosives were placed covertly into each of the twin towers and precision detonated after a jetliner impact.
Robert,
Go watch a building being brought down by controlled demolition. Where does the energy to destroy the building’s structure come from?
Slartibartfast,
You concluded that 17.4% of the total energy was used to collapse and pulverize the structure based on the time it took to collapse. You made your numbers fit the outcome. You performed the work of a mathematician brilliantly, but completely ignored the what energy should have been required to collapse and pulverize the structure.
If it takes 2 million joules to sheer the rivets/bolts/welds to free the floor, and 2 million joules to pulverize the concrete, and you only had 3 million joules of PE to start with, you can’t get the job done. If the job did get done, it would indicate that the floor took less than 2 million joules to break loose, or that it took less than 2 million joules to pulverize the concrete.
Bob,
I’d say that,
“I have said repeatedly that 17.4% of the gravitation potential energy of the WTC went into breaking the structure of the building and pulverizing the rubble… I have repeatedly said that I DID NOT INCLUDE THIS ENERGY IN MY CALCULATION OF THE HEAT GENERATED,”
addresses “the net Work necessary to shred the building into said rubble.”
I’m not going to argue the physics with you, Slart is handling that much more ably than I ever could. I will however point out that you’re flat out ignoring Slart accounting for something you say he doesn’t account for.
It’s pretty obvious which side of this debate I’m on. Since I’m adding nothing of substance, I’ll go back to the sidelines. I stand by my analysis of the debate, and will gladly defend it, but I won’t be dragged into a rehash of the old arguments.
Bob said:
“Furthermore, he doesn’t account for the disparity between the conditions of Towers 1 & 2 collapsing and the collapse of WTC 7. All three had molten metal and WTC 7’s debris pile, NOT CREATED BY 1.6 BILLION JOULES OF ENERGY, etc., was shown in the NASA thermograph as being the second highest hot spot in all of ground zero (more than 1300 degrees Fahrenheit)”
It’s a big enough pain to make this argument for WTC1 and WTC2. The symmetry of the buildings (and the collapses) is a big plus, modeling-wise. WTC7 had significant differences in dimensions, damage, and collapse – I would have to make an entirely new model to consider it. I’m not willing to do that unless you pay me for it.