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Electron band structure in germanium, my ass (2001)

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903 points tux3 | 3 comments | 01 Apr 25 12:25 UTC | HN request time: 0.446s | source
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jerf ◴[01 Apr 25 13:57 UTC] No.43546861[source]▶
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.)

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1. interroboink ◴[01 Apr 25 16:08 UTC] No.43548463[source]▶
> 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 the charge of the electron, after Millikan.  If you
    plot them as a function of time, you find that one is a little bigger
    than Millikan’s, and the next one’s a little bit bigger than that,
    and the next one’s a little bit bigger than that, until finally they
    settle down to a number which is higher.
    
    Why didn’t they discover that the new number was higher right away?
    It’s a thing that scientists are ashamed of—this history—because
    it’s apparent that people did things like this: When they got a number
    that was too high above Millikan’s, they thought something must be
    wrong—and they would look for and find a reason why something might be
    wrong.  When they got a number closer to Millikan’s value they didn’t
    look so hard.  And so they eliminated the numbers that were too far off,
    and did other things like that.  We’ve learned those tricks nowadays,
    and now we don’t have that kind of a disease.
Yeah, not sure I'm 100% agreed on that last statement (:

[1] https://calteches.library.caltech.edu/51/2/CargoCult.htm

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2. Eduard ◴[01 Apr 25 18:43 UTC] No.43550120[source]▶
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.

3. cycomanic ◴[01 Apr 25 19:25 UTC] No.43550468[source]▶
I would take Feynmans stories with a grain of salt, he was sometimes quite liberal with the facts when trying to make a point (in particular he liked to give the impression that he was the only smart guy in the room).

The actual history is a bit more complex and certainly is not reflected accurately in Feynmans retelling (maybe he was affected by confirmation bias?). See this stackoverflow discussion: https://skeptics.stackexchange.com/questions/44092/is-feynma...