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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