Just another first block astronomy class...
(unfortunately it was only about half the class because of the way I scheduled it)
Note the pumpkin on the far right. I let a couple of students (NN and SX) store their bootleg pumpkin for the day in the back of my room. As payment, I demanded they carve it with a physics theme.
Voila:
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| Ghostly parabolic position versus time graphs |
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| A free body diagram of the forces on an upside-down pumpkin on a pumpkin experiencing those forces. So meta, it's scary. |
Both of my kids recently took science tests and felt they didn't do well. I asked them each, "Well, how did you do compared to the class average?" Basically, neither was sure. Coincidentally, I am in the middle of grading a science test I just gave and thinking about where the class average is, what the distribution looks like and whether (and how) I should scale it.
In talking to my kids, I realize that my instincts on thinking about how well you did on a test being a relative thing comes from (1) being a physicist and (2) being a physics student. Physicists know better than most that EVERYTHING is relative: Velocity, Energy, Size, Temperature, Time, Length, etc. But, more on point, test scores in physics tend to be low. I don't know that I ever took a single physics test in 7 years of studying physics that wasn't scaled or manipulated in some way. It's not uncommon in college but it is actually commonplace in physics.
Here's my favorite story about this (you'll see why shortly ;) ):
First year of grad school, CMU. Dr. Russ's Quantum Mechanics course. First test. He folds the tests lengthwise after grading them for some reason and very soberly handed them back to us one by one. As each of us saw our percentages we slunk down low in our desks and didn't make contact with each other. I can still picture that big red 67% in a red circle beneath my name on that folded packet of work and feel it as defining me as a failure. I'm going for a PhD in this stuff and I can barely eek out a "D"?? Russ doesn't say a work about the scores, just dives into talking through each of the problems and pointing out the niceties of solving them elegantly. Finally, my friend Dan Cormier from the back row tentatively asks "Dr. Russ - how did people do on this test? What was the average?" The professor looked a bit sheepish and says, "Well, I don't know the average, people did all right - it's tough material and there was a wide range of scores.... the high score was a ... a ... umm, Ken - what did you get - was it a 67? Yes, the high score was a 67."
Well, it isn't often you feel such a reversal of emotion. I think I probably sat up straighter in my desk immediately after his answer. My buddy Phil Koran called me "The Quantum Cowboy" for a few months after that. Wonder why that nickname didn't stick??
So, kids - how did you do on your test, in a relative way?
The other day, I was talking about vectors in class. I soon noticed one usually attentive and expressive student (nontrivial in these days of mask-wearing!) (SX) was clearly bored. I instantly lost all interest in continuing the lecture and quickly transitioned over to having them do independent practice.
As often happens, this particular professional experience triggers a strong memory I have from graduate school. After passing my PhD qualifiers and chosen a field of study for my PhD, I rotated into the CMU Physics Department's monthly colloquium spot and did a presentation on computation neuroscience. I was pretty nervous but I thought the subject pretty interesting (obviously), but I did notice one of my favorite professors (Dr. Garoff - also an expressive and attentive person) was looking a bit bored and slightly distressed. I finished my talk as planned but didn't feel good about it. When I ran into him a few days later and asked him if he thought I was going down the wrong path for my PhD or anything, he was very surprised and said something like "I really should monitor myself more because I don't want people reading into my expressions! I was having a bad day for completely personal reasons and was distracted by my own thoughts during your talk - it had nothing to do with you."
So, why with a sea of faces to chose from and a captive audience and a mission to perform am I still so susceptible to random feedback from certain faces? This was on my mind when I read about how neuroscientists have recently determined that worms, while eating their way thought the dirt will release a neurotransmitter when detecting high levels of nutrients in the local soil which causes them to slow down instantly.
This mechanism suggests that neural pathways are constantly being adjusted by pretty simply cues from the environment. I thought "Aha - I am the worm and when the soil comes back as not very tasty, my brain tells me something is wrong. It is as simple as that."
It all comes back to Mon Oncle d'Amerique!
I recently read the following quote from Dr. Fan Wang:
"... All perceptions are illusions, but just because it's in the head
doesn't mean it's not real. Everything's in the head."
And there it is: as succinctly put as possible. There is simultaneously an objective reality out there and our own experience of it, which is neither objective nor 'out there'. Therein lies the problem with all oversimplifications and the source of much confusion. Imagine the good that could come from wide-spread understanding of this simple truth.
(as an aside and a plug: this is why we need science: Reality can not be understood simply through your subjective, passive experience of it)
You know, this is not so much a dichotomy as it is an example of a Bohrian 'Profound Truth':
All we know is what is in our head: that is our reality. However, what is in our head is an illusion. Illusions are our experience of reality.
(Back to shadows on the wall and Plato, anyone? Neuroscience brings us full circle!)
