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Electron band structure in germanium, my ass (2001)

pages.cs.wisc.edu

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Re: Electron band structure in germanium, my ass (2001)

#22

hahaa, I love it! That's right there is engineering and true work and dedication. Can hear the frustration and it's 100% warranted. I wish universities were better equipped for what you pay. Where is all that money going anyways? Leaking like free electrons?

The gym, I think. Usually the brand new buildings, too.

Re: Electron band structure in germanium, my ass (2001)

#25

I took some effort to change my research interest from computer vision to DFT calculation in quantum chemistry. Honestly, I'm kind of frustrated now, too many work is close-source in this area. The research paper will tell you everything except how to reproduce this work in minimal effort, it's like they are hiding something. They also using a `Origin` to plot and MS Word to write paper, which is also non-free licens…

I miss OriginPro in my undergrad when we had campus licenses for, before moving to matplotlib for data visualization. matplotlib is simply too disappointing for making publication quality figures. The most recently encountered problem is how to plot with a broken x-axis, which is one of the most basic need in physical science but requires a non-trivial amount of hacking to get with matplotlib.

Open source tool or not, I don't care at all as I get the science right. I have already enough frustration dealing with my samples, so I simply want the least frustration from the software I use to plot.

Re: Electron band structure in germanium, my ass (2001)

#26
post #4

(2000) (at most: https://web.archive.org/web/20001031193257/http://www.cs.wis... )

> (2000) It was probably actually written sometime prior to June 1999, because that's when the author got his Physics BS at Stanford ( https://pages.cs.wisc.edu/~kovar/cv.html ). I kinda want to know more of the backstory around this. What grade did he get? Or was this a private venting exercise he later put up on his webpage, once he was well clear of the course? The author did eventually go into CS, I wonder if thi…

Yeah I want to say I remember this making the rounds (remember email forwards?) during my first year of undergrad ('99-'00) but I'm a bit fuzzy on the exact timing.

Re: Electron band structure in germanium, my ass (2001)

#27
One of my Core Memories when it comes to science, science education, and education in general was in my high school physics class, where we had to do an experiment to determine the gravitational acceleration of Earth. This was done via the following mechanism: Roll a ball off of a standard classroom table. Use a 1990s wristwatch's stopwatch mechanism to start the clock when the ball rolls of the table. Stop the stopwatch when the ball hits the floor.

Anyone who has ever had a wristwatch of similar tech should know how hard it is to get anything like precision out of those things. It's a millimeter sized button with a millimeter depth of press and could easily need half a second of jabbing at it to get it to trigger. It's for measuring your mile times in minutes, not fractions of a second fall times.

Naturally, our data was total, utter crap. Any sensible analysis would have error bars that, if you treat the problem linearly, would have put 0 and negative numbers within our error bars. I dutifully crunched the numbers and determined that the gravitational constant was something like 6.8m/s^2 and turned it in.

Naturally, I got a failing grade, because that's not particularly close, and no matter how many times you are solemnly assured otherwise, you are never graded on whether you did your best and honestly report what you observe. From grade school on, you are graded on whether or not the grading authority likes the results you got. You might hope that there comes some point in your career where that stops being the case, but as near as I can tell, it literally never does. Right on up to professorships, this is how science really works.

The lesson is taught early and often. It often sort of baffles me when other people are baffled at how often this happens in science, because it more-or-less always happens. Science proceeds despite this, not because of it.

(But jerf, my teacher... Yes, you had a wonderful teacher who didn't only give you an A for the equivalent but called you out in class for your honesty and I dunno, flunked everyone who claimed they got the supposed "correct" answer to three significant digits because that was impossible. There are a few shining lights in the field and I would never dream of denying that. Now tell me how that idealism worked for you going forward the next several years.)

Re: Electron band structure in germanium, my ass (2001)

#28

It takes a special kind of mind to appreciate this short post, not as fiction, but as truth and also as a jab at the physics sciences in general.

Why is it a jab at physics? It's honest and beautiful -- I imagine this is exactly what an experience on the cutting edge of experiment is like! :D

Making this measurement (an ancient discovery) with latest equipment is easy, but imagine what it might have been like for the people who actually discovered this property of germanium. Our tools/probes cannot advance much faster than our understanding of a (related) subject -- we are constantly inventing/improvising tools using cutting edge scientific knowledge from a related field.

Re: Electron band structure in germanium, my ass (2001)

#29
post #27

One of my Core Memories when it comes to science, science education, and education in general was in my high school physics class, where we had to do an experiment to determine the gravitational acceleration of Earth. This was done via the following mechanism: Roll a ball off of a standard classroom table. Use a 1990s wristwatch's stopwatch mechanism to start the clock when the ball rolls of the table. Stop the stopw…

I think if you showed not only the point estimate, but also some measure of uncertainty like standard deviation, it should have given you a passing grade. It's hard to say why an answer like 6.8 +- 5 is wrong.

Even if you don't yet have formal statistical chops, it should be at least possible to show cumulative distribution function of results that will convey the story better than a single answer with overly optimistic implied precision.

Re: Electron band structure in germanium, my ass (2001)

#30
post #3

I spent a good minute looking at the exponential in graph, ignoring all the actual data points, thinking to myself that the experiment does show an exponential relation. Where's the lie? Guess that's the power pictures have over words.

There should be some more examples in how to lie with statistics?
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