A Lesson In Teaching Physics: You Can’t Give It Away

[kuruman]

A central principle of Physics Forums regarding homework help is not to provide solutions on demand but to guide students along a path to the answer.  The rationale behind this principle is articulated in the familiar saying, “If you give a hungry man a fish, you feed him for a day; if you teach him how to fish, you feed him for a lifetime.”  That said, I will quote another familiar saying, “You can lead a horse to water, but you can’t make him drink.”  Then I will blend the two into “You can teach a hungry man how to fish and lead him to the water, but you can’t make him fish.”
This mélange epitomizes a conclusion I reached after decades of teaching minds, some hungry some not, how to think. How I reached this conclusion and how I eventually came to terms with it are the subject of this article.
The seeds
When I began graduate school, my duties included helping with grading hourly exams in large classes (150-200 students).  Here is the exam question that started it all.
An...

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[Swamp Thing]

An electron of charge −e enters a region of uniform magnetic field B with velocity v directed into the page.

Isn't this a bit confusing, given that the figure shows the electron moving "within the page" ? Or is it a deliberate trap?

 

[kuruman]

Good catch! It should read "An electron of charge $−e$ enters with velocity $v$ a region of uniform magnetic field $B$ directed into the page." I cut and pasted in the wrong place. The typo has been fixed.

 

[vela]

I couldn't help but notice the irony in that you ignored what your mentor David told you just as your students ignored what you told them.

 

[gmax137]

I found this to be a very interesting read. Thinking back to my school days, I don't think I had the maturity and good sense to have worked through all of the booklet. My main strategy was to carefully read the textbook, and pay close attention in my classes. I don't think I appreciated how important it is to do the problems. I didn't figure that out until my third year.

I will say that I did note whenever the professor would say "this will be on the exam." Sometimes they didn't say it explicitly but "I could tell."

 

[kuruman]

I couldn't help but notice the irony in that you ignored what your mentor David told you just as your students ignored what you told them.

Yes, I didn't realize it immediately. At first I thought that David wanted to spare my feelings by not saying "I told you so." His smirk was more devastating. It made me see the similarity between him "telling" me and me "telling" my students. Disregarding good advice is a common trait among humans.

 

[hutchphd]

Are you aware of similar attempts by others? I think it is very good strategy and particulary like the "leave it in Algebraic form on test day" part. Also cuts down on my least favorite question: "will that be on the test?" My personally favorite ploy was allowing a single-sided 8.5x11 inch cheat sheet (this was pre-printer/computer days and microfiche was not allowed)
Did you publish the list of problems for public consumption? Might be interesting to have generic lists for the intro courses

 

[kuruman]

Are you aware of similar attempts by others?

I am not aware of similar attempts by others.

Also cuts down on my least favorite question: "will that be on the test?"

And it cut down on my least favorite question: "do I have to know this?" I made sure that the booklet covered all the aspects of understanding and skills that I expected students to acquire in the course. However, I never said "If its not in the booklet, you don't have to know it."

Did you publish the list of problems for public consumption?

They were available to students through the Blackboard platform that my institution had adopted. A password was needed for access so no, they were not available for public consumption. However, the very first three or four booklets came into being before course websites were commonly available. They were literally booklets consisting of paper sheets stapled together and made available to students at a nominal fee to defray the photocopying costs.

 

[berkeman]

Are you aware of similar attempts by others?

I am not aware of similar attempts by others.

In my last physics course as a sophomore many years ago, the professor did use the notebook technique to frame the homework and exam questions. It had about 100-120 problems in it, similar to yours, and he had the same policy that exam questions would be from the booklet.

It was a very large class (around 500 students), and I was really enjoying Physics at the time (but would later choose EE for my specialty starting in my junior year). I worked through every problem in the booklet during the course, and was left with only 2-3 that I could not solve going into the last couple weeks and preparing for the final exam. I went to a large study session in the lecture hall the week before the final, where the professor and TAs were available to help with questions. I was first to raise my hand and asked about one of the last problems in the booklet that I was having trouble with. The professor smiled (he knew me) and asked the rest of the large group if there were any problems near the beginning of the booklet that they wanted help with. About 30 hands shot up, so I realized that the session wasn't for me, and headed off to study more on my own.

During the final, I was able to work through all of the problems pretty quickly, except one that was one of the problems that I had not been able to figure out in the booklet. Fortunately I had about 10+ minutes left in the exam to keep working on it, and thanks to all of the time I'd already put into working on it during the semester, I was able to figure out the key concept that I needed to apply and was able to solve the problem. I was so happy as I was finishing up the solution that I started quietly laughing to myself and looked up to see one of my favorite TAs from the course who was sitting in the front of the lecture hall proctoring the exam. He saw the expression on my face and just smiled at me.

So I agree that the handbook approach can work well, especially in larger lower-division classes. But I also agree with what you wrote, that it works best for students who are highly motivated to learn and to do well.

 

[Nik_2213]

My last Math teacher pre-Uni had the most unfortunate reputation of asking 'trick' questions. As, that year, none of us were noticeably 'gifted', we soon learned that 'obvious' replies were probably superficial, wrong. This led to paranoid mind-set where no-one dared reply without a 's_l_o_w count' to study what we'd now call an 'IED'...

"Red wire ? Green ? Blue ?? The grey 'Coax' ???"

This led to trap where 'simple' schol-paper problems, meant to shake out the 'rote-learners', were more time-consuming than the 'hard' ones intended to make you think...

Shades of Sherlock's "When you have eliminated the impossible, whatever remains, however improbable, must be the truth..."

By cruel irony, I ran into the guy about a decade later at local 'all-formats' computer club: He was so proud of his Commodore PET, but he'd seen my Apple ][+ 3D Astronomy program, published as cover-article in small-press. I'd only used basic Trig plus compound Sin/Cos formulae for the stellar coordinates' tri-axial rotations, but I'd done them right...

I caught my breath, apologised that I'd not been one of his better students. He replied to effect that no bad students had attended his course.
Let's put it this way: a life-time along, I still cannot figure if that was insult, neutral or compliment...