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Electron band structure in germanium, my ass (2001)

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

#191

Post by Natsu »

don-code wrote: post #161
Natsu wrote: post #141

Earlier quoted context omitted.

It's funny, because while that's a terrible educational experience, you actually learned some important lessons despite them. I remember the first time I found out that the software documentation I had been relying upon was simply and utterly wrong. It was so freeing to start looking at how things actually behaved instead of believing the utterly false documentation because the world finally made sense again.

Sometimes it's not even rare that documentation is wrong. The documentation for a vendor who I won't name - but might be at Series J and worth north or $50 billion - seems to be wrong more often than it's right. We frequently say, don't blame the tools, it's you. That pushes "blame the tools" outside of the Overton window, and when we need to blame a tool, we're looked at like we have five heads. Ten years ago, I was…

In my case, it was egregiously bad, because someone had cribbed docs from an entirely separate scripting language that did almost the same things. Most of the same features were there, but the docs were utter lies, and failures were silent. So you'd go down the wrong branch of an if statement because it wasn't checking the conditions it claimed to check.

Once I started actually testing the scripts against the docs and rewriting them, life got so much better. The worst part is that it had been that way for years and somehow nobody noticed because the people using that horrible scripting language mostly weren't programmers and they'd just tweak things until they could happy path just enough to kinda-sorta work.

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

#192

Post by incognito124 »

nottorp wrote: post #30
abhink wrote: 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?

Believe it or not, there's an entire book about it!

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

#193

Post by cycomanic »

jerf wrote: 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…

On the other hand my experience as both a graduate and professor teaching students are equally discouraging.

1. Most students don't want to have to think. As a student I was always annoyed that we'd be given exact instructions with an exactly know result to reproduce, while this is generally not how real experiments work. So when I designed an experiment I wrote instructions that reflected more the real life experience, I.e. instead of "place the lens A 10mm from object B" it was "place the lens one focal length away from the object, to know the focal length of your lens you can use a light source at Infinity (far away)." after I left my university the instructions were reverted back because students complained that they didn't get step by step instructions.

2. Students dutifully write down a measurements that is of several orders of magnitude with absolutely no acknowledgement/discussion. I have seen speed of light barely faster than a car and mass of a small piece material in 100s of kg (usually because students forget a nano or giga in a calculation), without any discussion that the result is nonsensical.

3. Similar they make a fit like the one in the OP and don't even discuss the error bars. Or (and that's already the better students) they make a fit with tiny error bars, but get the wrong result (typically due to some mistake like above) and in the discussion say the difference to an expected error is due to measurement error.

Now I also know that there are crappy graduate students who teach because they are teaching the "only get the correct result" but it's often very difficult to improve teaching because students will immediately complain that they have to adjust to changes.

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

#194

Post by don-code »

mandevil wrote: post #182
Natsu wrote: post #141

Earlier quoted context omitted.

It's funny, because while that's a terrible educational experience, you actually learned some important lessons despite them. I remember the first time I found out that the software documentation I had been relying upon was simply and utterly wrong. It was so freeing to start looking at how things actually behaved instead of believing the utterly false documentation because the world finally made sense again.

I took and then TA'd a class where the semester long project was to control robots (it was a software engineering principles class, the actual code writing could be done in a single weekend, but you had to do all the other stuff of software engineering- requirements analysis and documentation etc). We had a software simulator of the robots, and the first lab was everyone dutifully writing the code that worked great o…

Just out of curiosity, were you up-front after the fact that this was part of the exercise?

We had a first-semester freshman year course that all incoming students were required to take. The first assignment in that class was an essay, pretty typical stuff, I don't even remember what about.

A day after handing it in, roughly half of the class would be given a formal academic citation for plagiarism. That half of the class hadn't cited their sources. "This one time only", the citation could be removed if the students re-submitted an essay with a bibliography.

While it was obvious, in hindsight, that the point of the exercise was to get you to understand that the university took plagiarism seriously, especially with the "this one time only" string attached, it felt dishonest in that nobody ever came out and said so. I luckily wasn't on the receiving end of one of those citations, but I can only imagine the panic of a typical first-semester freshman being formally accused of plagiarism.

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

#195

Post by fluoridation »

shadowgovt wrote: post #181
fluoridation wrote: post #163

Earlier quoted context omitted.

Surely you can simply use a ruler and rotate it away from the parallel to achieve any arbitrary scale, right?

If you happen to have a good ruler (again, 1720s... Those also cost money or time to make). A ruler and a T-square would work. But still, it's more complicated and requires a lot more bench to secure things in place at angles than folding a piece of string in half.

Well... Yeah. It costs money and/or time to make things. That's as much true now as it was back then, but I don't think a ruler would have been particularly difficult to make, even with 18th century technology.

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

#196

Post by npongratz »

ryandrake wrote: post #166
npongratz wrote: post #129

Earlier quoted context omitted.

Sure, we could speculate about his true unstated reasons for marking wrong my answer. I highly doubt the science teacher marked me wrong for "dumping", though. He had every opportunity to explain that to me after I got my exam graded and I asked him about it. Then he had the opportunity to explain that face-to-face with my parents. He did not do so. He said that while I got the answer right, he was "mad", thus the ma…

Good experience to prepare you for the rest of your academic and working life where your performance rating will often be strongly influenced the evaluator's current mood or biases. Or the police officer's mood when you get pulled over. Or most other authority figures' feelings when they're making decisions that affect you. It's unfairness all the way until we die.

Authoritarianism, everywhere and in all forms, seeks to shut down curiosity and critical thinking.

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

#197

Post by Eduard »

interroboink wrote: post #96
jerf wrote: 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…

> Right on up to professorships, this is how science really works. Reminds me of Feynman's "Cargo Cult Science" essay[1] One example: Millikan measured the charge on an electron by an experiment with falling oil drops and got an answer which we now know not to be quite right. It’s a little bit off, because he had the incorrect value for the viscosity of air. It’s interesting to look at the history of measurements of…

context :

https://en.m.wikipedia.org/wiki/Oil_drop_experiment

Assuming Feynmann's statement is true, I find it even more remarkable that Millikan's electron charge research was published in Science AND won him a Nobel Prize without anyone noticing the very apparent mistake of using an incorrect value for the viscosity of air.

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

#198

Post by SJC_Hacker »

sdenton4 wrote: post #66
mystified5016 wrote: post #48

Earlier quoted context omitted.

The way boats historically measured speed was by dragging a rope behind them. The rope has knots tied with exact spacing. You drop one end of the rope in the water, and count how many knots pass you in a given time. That's then your speed in knots.

Using this method repeatedly to guess how far you've moved over the course of days is, historically, a fantastic way to crash into the side of France in the middle of the night.

Well the other problem is knowing where you are. The sun/stars can give you latitude. Longitude was nearly impossible until the advent of the marine chronometer in the latter part of the 18th century, and not "standard" on ships until the mid-1800s. There were earlier versions, which had poor accuracy and were not much better than dead reckoning

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

#199

Post by butlike »

don-code wrote: post #87
jerf wrote: 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…

This is, more or less, exactly what happened when I took Electronics I in college. The course was structured in such a way that you could not move on to the next lab assignment until you completed the one before it. You could complete the lab assignments at your own pace. If you failed the lab, you failed the class, regardless of your grade. The second or third lab had us characterize the response of a transistor in…

you should have gotten an A for being a real engineer
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