By Christopher Moore
My views on those that think the US government intentionally demolished the WTC complex should be very clear. I received an interesting comment today on one of my YouTube videos about thermal expansion:
NIST claims thermal expansion caused the collapse of WTC7 by the fires?
Is there anyway you could post a comment on whether the degrees of heat caused alot of thermal expansion. or just check the NIST’s report to see if they have any calculations For this?
They’ve allowed only 3 weeks to go through their documents to allow rebuttels and corrections. They call Thermal expansion of steel a “New phenomenon” which is weird when you have a video explaining thermal expansion a year prior
Obviously, this is in reference to the recent annoncement by NIST that progressive collapse brought about by weakened steel was the reason that the WTC7 building fell. I’ll respond as best I can.
Is there anyway you could post a comment on whether the degrees of heat caused alot of thermal expansion. or just check the NIST’s report to see if they have any calculations For this?
Yes. I am certain that thermal expansion occured and that it was probably significant. I am a materials scientist, though my research focus is on semiconductors and nanomaterials, so I have not personally studied anything to with the WTC in detail. However, the peer-reviewed research on the collapse of the Twin Towers points in this direction. I suggest starting with the following journal article:
“Behaviour of lightweight composite trusses in fire – A case study,” STEEL AND COMPOSITE STRUCTURES 7 (2): 105-118 APR 2007
Continuing …
They’ve allowed only 3 weeks to go through their documents to allow rebuttels and corrections.
This is merely for the report. The issue will still be argued and studied in the scientific and engineering community because it is incredibly interesting (see below).
They call Thermal expansion of steel a “New phenomenon” which is weird when you have a video explaining thermal expansion a year prior
The idea that materials expand and contract in response to thermal inputs is hardly new. My assumption is that what NIST means by “new phenomenon” is the thermal expansion of the steel trusses to the degree that allowed for collapse. This is new! There is truth to the 9/11 Troofer claim that before 9/11, no steel structure of the magnitude of the WTC buildings had ever fallen due to fire. The collapse of the three WTC buildings was unprecedented. If you would have asked an engineer before 9/11 if such a collapse scenario was possible, then they probably would have told you that it was very unlikely. That is precisely why the collapse has been studied in great detail by structural engineers and fire safety engineers and why there are numerous peer-reviewed articles in scholarly journals on this subject. In fact, the collapse has led to stricter building codes, as evidenced by the following article:
“Progressive collapse of structures: Annotated bibliography and comparison of codes and standards,” JOURNAL OF PERFORMANCE OF CONSTRUCTED FACILITIES 20 (4): 418-425 NOV 2006
I’m a little confused by NISTs recent report. I had assumed that this had always been their opinion on WTC7. Also, the claim that there were no “blast events” may be disingenuous, since there are credible reports that the fuel-oil tanks on the 3rd or 4th level (I can’t remember which level, precisely) had blown, which would not be suprising.
By Christopher Moore
I was looking up information about whether there is any pedegogical research that shows “clickers” are better than simple flash cards. I’m young, so when I first started teaching I was hip to all of the fancy technology. However, as I’ve progressed in my teaching, I’ve learned that anything you can do with technology can be done just as well without it. Apparently, I was right.
Anyway, I stumbled onto Teaching Astronomy, and Paul Robinson has a great article about Ben Stein’s new movie Expelled. I’ve written on this topic before, but from a slightly different perspective.
By Christopher Moore
Last semester I had a student working with me on building a sputter deposition chamber. We spent a lot of time waiting for parts, but we did manage to get some very necessary pieces together. Andy and I designed and fabricated a collar system for supporting the weight of the rather large 6-way cross we will be using for the vacuum chamber. Here is a picture:
The support collar consists of all the shiny aluminum on the black table that clamps around the stainless steel chamber and holds it upright. Since I took this picture, I have mounted the sputter gun on the left side flange. Under the table is a small (and brand-new!) turbo-pumping station with an oil-free diaphram backing pump. I was able to scrounge around the department and find a nice little pump that we will use to circulate cool water through the sputter head to maintain reasonable temperatures.
I already have a student lined up to work on this system next semester. We first have to design and fabricate a sample stage. The electrical feedthrough on the right flange is intentionally there for sample heating via DC resistive heat. After that, we begin calibration by sputtering aluminum films and measuring their thicknesses.
There is a purpose behind the shiny toys, of course. By the end of the next academic year we will be growing semiconductor nanowires in aluminum oxide porous films. I even have money to staff my lab for this purpose next summer.
By Christopher Moore
I realize I haven’t written an update on the scanning tunneling microscope (STM) in a while. I had mentioned about a month ago that the STM was working; however, Donnie left for Old Dominion University via our 3/2 engineering program and I haven’t yet recruited a student to pick up the pieces. I’m working out how we can computerize this thing while still keeping the total cost below $200. I’ve got some ideas!
Pictures after the jump!
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By Christopher Moore
Carlwin has the following question about energy:
I dont know if our solution is right, but here’s the problem: Compute for the energy given off by a gas doing 200 J of work and losing 1350 J of its internal energy to the environment
Normally, I don’t respond to these types of questions for two reasons: (1) I don’t do other people’s homework, and (2) no mention was given to what their solution was, so it makes it hard to comment on where their reasoning is correct or incorrect. The forums are sometimes useful for these types of questions, but usually without having shown some initial effort, most questions like this die from lack of response.
So why am I going to respond? Because the question is either a trick question or awkwardly worded, which means it is the type of question that I hate and the type that typically leads to very little learning on the part of the student. This isn’t Carlwin’s fault. This is the fault of the person that assigned this question.
Why is this question a poorly formed question? Because, I could pose this question to a room full of PhDed physicists and get 2 or 3 different answers, all of which could be justified.
The question specifically asks how much energy the system “gives off”. The answer is 1350 J.
Anytime you see the buzzwords “internal energy” and “work”, think of the 1st Law of Thermodynamics: the change in the internal energy equals the sum of the change in the heat and the change in the work, or
.
A system has a certain amount of internal energy. That is all the energy it has available to “give off”. If it looses 1350 J of energy, then it lost 1350 J of energy. Period. It doesn’t matter whether that energy was work or heat.
However, it seems like the questioner meant to ask how much heat does the gas give off. In that case, the answer would be 1150 J.
So, either the question is a “trick” question or the question is a poorly formed question. Either way, I’m not sure how you would properly assess a student’s understanding via this question.
By Christopher Moore
It sure didn’t take long for the emails to start pouring in after I made this comment:
I also get about 1-2 emails a week from people who have developed a “new paradigm” in physics or believe their 5 second video of the collapse of the Twin Towers is proof that the US government planted explosives that caused the collapse, so I’ve seen all manner of the irrational.
Here is a good example from my inbox:
Here’s where we’re at:
The 9/11 Truth movement has a scientific explanation of what happened to WTC 7 >>> Controlled Demolition. We also have evidence, several videos of its collapse, all of which contain several features of controlled demolition. No Debunker has made the claim that controlled demolition would not scientifically explain the collapse of WTC 7. No Debunker has come up with an alternative scientific theory to explain the features on the WTC 7 collapse videos, including the global free fall speed of collapse. We also should not allow political theories to pollute science. It been 6 years since 9/11. 6 years of unrefuted scientific evidence is long enough to declare with certainty that, yes, indeed, this was a controlled demolition.
At some point, we need to move along, folks.
I will attempt an answer after the jump, though I can assure you that this will only increase the amount of email I get from these folks.
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By Christopher Moore
I’m back in Farmville after spending the weekend in College Park, MD being taught how to teach. (Technically, I’m in Richmond working on research right now, but I will be in Farmville tonight.) I didn’t get an opportunity to blog about the workshop much as it was going, because the schedule was very dense and filled 12 hours of each day. I’m very tired.
The highlights: Eric Mazur of Harvard and Edward Prather of the University of Arizona. These two could not be any more different in terms of personality and presentation. However, they both managed to completely convince me of the power of Peer Instruction. I’m sold. (I even learned a little astronomy during Ed’s workshop!)
I took notes on my fancy tablet PC, so rather than re-hash most of the meat from memory, I’ll just upload PDFs of those notes when I get back to my office tomorrow. But I will leave you with the number one technique I walked away with that will find use on day one this coming semester: Think-Pair-Share using color-coded cards.
By Christopher Moore
Uhhgg!
The most powerful atom-smasher ever built could make some bizarre discoveries, such as invisible matter or extra dimensions in space, after it is switched on in August.
But some critics fear the Large Hadron Collider could exceed physicists’ wildest conjectures: Will it spawn a black hole that could swallow Earth?
Or spit out particles that could turn the planet into a hot dead clump?
All I can say is I sort-of know what’s going through the minds of the principle investigators working on the Large Hadron Collider at CERN. We have a small inertial electrostatic confinement fusion reactor in my lab, and I do get a little tired continually assuaging the fears of others. I also get about 1-2 emails a week from people who have developed a “new paradigm” in physics or believe their 5 second video of the collapse of the Twin Towers is proof that the US government planted explosives that caused the collapse, so I’ve seen all manner of the irrational.
People fear and believe the dumbest things.
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