Tuesday, July 1, 2014

Rules of Teaching - 7

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Whether they admit it or not, students do learn from their teachers...if nothing, at least how not to teach.


And whether they admit it or not, teachers too learn from their students...if nothing, at least how to doze with head erect and eyes open.

But if there is a class of students eager to learn and a teacher willing to teach, nothing can be a more happy hour.

That teachers learn from their students has been openly admitted by none other than the greatest physics teacher of my time, Feynman:


...The questions of the students are often the source of new research. They often ask profound questions that I've thought about at times and then given up on, so to speak, for a while. It wouldn't do me any harm to think about them again and see if I can go any further now. The students may not be able to see the thing I want to answer, or the subtleties I want to think about, but they remind me of a problem by asking questions in the neighborhood of that problem. It's not so easy to remind yourself of these things.

So I find that teaching and the students keep life going, and I would never accept any position in which somebody has invented a happy situation for me where I don' have to teach. Never....


It is clear from the context that Feynman is talking about his undergraduate students and not research students that he didn't have many. So, it looks Feynman wouldn't have accepted a faculty position at our TIFR. Never.

In order to learn from one's students, a teacher must be shameless and his students fearless. Indeed the business of a teacher is to remove fear of the subject from his students' minds and of himself.


I was indeed fortunate that I was just 21 when I started teaching undergraduates at IIT KGP in 1965 and my students were just 3 or 4 years younger to me. Pretty soon I learned not to feel shy with them, and they, not to fear me at all. Word spreads in a small campus, and shamelessness becomes a habit, going right into the post-retirement blogging phase.

That a student from whom you want to learn mustn't fear you, and that you shouldn't shy away from him, is clear from another Feynman quote:


...I also met Niels Bohr. His name was Nicholas Baker in those days, and he came to Los Alamos with Jim Baker, his son, whose real name was Aage Bohr. They came from Denmark, and they were very famous physicists, as you know. Even to the big shot guys, Bohr was a great god.

We were at a meeting once, the first time he came, and everybody wanted to see the great Bohr. So there were a lot of people there, and we were discussing the problems of the bomb. I was back in a corner somewhere. He came and went, and all I could see of him was from between people's heads...

...Then the son told me what happened. The last time he was there, Bohr said to his son, "Remember the name of that little fellow in the back over there? He's the only guy who's not afraid of me, and will say when I've got a crazy idea. So next time when we want to discuss ideas, we're not going to be able to do it with these guys who say everything is yes, yes, Dr Bohr. Get that guy and we'll talk with him first."...


No student of mine at KGP was ever afraid of me, I guess. After the class, a few would regularly troop into my office to get clarifications from me but didn't know that I was clarifying for myself most of the time. And quite a few used to land up at odd times in my Qrs and sit down and fire their questions at me. And that way everyday was a viva for me.

One fine Sunday morning when my wife and I were planning to go shopping to Gole Bazaar, Vibhat Nair walked in and sat down with a glum face. And I asked him what the matter was and he said:

"Give me without math and equations the answer to my query: In classical electrodynamics, I read that a charge circulating would emit em radiation of the same frequency as its own circular motion. But we know that protons in a synchrotron go round at low radio frequencies but they emit hard X-rays. How do they do it?"

That query was new to me and I told him I have no offhand hand-waving answer to that and asked him for a day's time. 

The next day I happened to see him near our locker-stand and stopped him and asked him for a paper and gave him my answer with no equations at all but just a simple diagram. And I can never forget the understanding twinkle in his face. And that query together with a few more of Alabhya Singh and mine own gave me an article titled "Radiation from circular orbits: some conceptual questions" in an educational journal that I am happy with:


http://iopscience.iop.org/0031-9120/30/1/003


And here is the story of how I learned a lot quickly from my students in the fourth year lab at KGP in the mid-1990s:

During the early 1960s we had fantastic state-of-the-art electronics labs in our UG labs at our Andhra University in Vizagh. We had to handle all those glowing vacuum tubes like diodes, triodes, tetrodes, pentodes, hexodes, VR tubes, thyratrons, klystrons and magnetrons. And do experiments building audio amplifiers, radio amplifiers, video amplifiers, IF amplifiers, oscillators, mixers, converters, modulators, demodulators; and build on our own a complete superhet radio receiver, calibrate it, and receive music from AIR and Radio Ceylone; and then go on to wave guides in the microwave lab and measure real and imaginary parts of the dielectric constant of benzene and make Cole-Cole plots and such hi-fi things.

And in my interview for joining at IIT KGP as a faculty, Professor HN Bose asked me questions on these (guided by me) and took me in at once...the UG labs at IIT KGP then had primitive experiments in their fourth year lab with few teachers willing to sit there, and I was pushed into that lab class from the very beginning (and retired from there).

So in the beginning it was child's play for me to look after the students in that lab and most of the time I was reading up QM and EM and GR books for my own benefit, sitting quietly in one of the four gang of teachers' chairs there, interrupted by periodic trips to the canteen; and doing my Ph D in theory with SDM.

And my seniors were lab-in-charges and they gradually replaced vacuum tubes with transistors and then chips in about 3 decades. But I still used to feel that 4th year students could do more electronics experiments and learn and enjoy. 

All of a sudden, in 1995, our new HoD, Prof MLM, felt that I was doing very little for the department and the first thing he did was to make me lab-in-charge of the fourth year lab, a coveted post...it adds to one's CV I was told...

And so the first thing I had to do was to get to know all the experiments that the students were then doing, as quickly as possible. And, instead of asking my predecessor, I decided to sit with one pair of students each day for all of 3 hours and pretend to take their lab viva...and in about a month I covered all the extant experiments thoroughly...learning from my students all the time without, perhaps, their knowing it. 

And then I replaced all the single beam oscilloscopes with double-beam ones, soldering irons with bread boards, old signal generators with latest ones and introduced many new experiments with chips, and all in all I felt happy.

In the very next semester, I was kicked upstairs into a new position created for me called: 'Guide & Adviser of the 4th Year Lab'; and my ex-student, Prof SKR, was made its lab-in-charge. And I learned much more from him, and for the next decade till my retirement we two formed a team like that mother-in-law cum daughter-in-law team in a TV ad for Surf Excel, or some such, of that time. 

Prof SKR (HoD) was here in my Hyderabad home last summer for a couple of hours to look me up and nostalgize..

Great time I had learning from my students at KGP...I thank them all hereby...


...Posted by Ishani   

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