Thursday, December 4, 2014

The Other Pendulum - Repeat Telecast

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My first day in the Physics Lab at our blessed Andhra University in Vizagh has been a memorable nightmare for me.

Our Physics Department, I now see, was weak in theory but redoubtable in its labs.    

We were but a dozen greenhorns in our B. Sc. (Hons) class, all of us fresh from mofussil colleges that had no labs to sing about. And we twelve were eminently on our own with no concept of lab partners (in crime), no cookbooks, and no help other than the glossy Worsnop & Flint which was forbidding in its thickness and style.

And I was allotted an experiment called Borda's Pendulum, of which I was as ignorant as a forlorn chicken led into a jungle.

Our Demonstrator took our roll call and showed each of us our places and left, never to return for three hours, to take the valedictory roll call.

Our Lab Attendant (I still remember his gruesome face) gingerly handed me a stopwatch under signature with the threat:

"That costs Rs 500...ten times your caution deposit"


Returning to my stand I saw a white wall in front of which was hanging from the ceiling by a steel wire a massive iron ball of about 4 inches diameter on whose face was affixed a pin with its tip looking down dejectedly. 

And on the wall was scribbled the weight of the 'bob', its diameter, and the length of the hanging wire.

On a stool opposite was a retort stand to which was fixed by a clamp and screw a 'telescope'.

The idea was that I should focus the telescope on the tip of the pin...and then the rest is cakewalk.

The trouble was with the semi-infinite degrees of freedom that my telescope had.

First, the retort stand can moved hither and thither and rotated clockwise and anti. Then the telescope can be moved in and out into its frame. Then it can be pulled up and down. Again, it can be tilted this way and that. And the scope had its front and back lenses that could be screwed and unscrewed tight and loose. There is a name for them...objective and eyepiece. The eyepiece can be rotated and pulled back and forth till it falls down on the ground. Then the eyepiece is not a single lens but a combo called Huyghens...bless his soul. Then it had cross hairs that were as delicate as...well...strands of hair. Then comes the focusing screw that allows the tube to be moved back and forth on a rack and pinion till the cows come home.

I don't think there is any other insurmountable challenge that I faced in all my lab life then on.

First I peered tentatively into the eyepiece with one eye closed....I didn't have practice at winking for any length of time before that.

All I saw was a white blur...that was the garbled wall.

And peering feverishly into my telescope, I spent all my 3 hours making all the adjustments known to man or beast.

The result...the white blur became more and more pronounced and threatening.

At the end of the class I sought the help of our Demonstrator after he took his parting roll call. He came and focused the telescope on the tip of the pin in one  minute and asked me to peer...and lo and behold...it was like seeing through my good old Viewmaster.

But the bloke undid every adjustment he made and worse...and left.

It took all of 3 days for me to get to know the technique...Prof S. K. Dattaray (sadly no more) used to call it 'kaida'.

Then on I became an expert in focusing all sorts of scopes, and never looked back.

And, at IIT KGP, I did to my students what my wicked Demonstrator at AU did to me...with a vengeance....  

And was cursed by them that one day I would become a one-eyed Jack ;)






...Posted by Ishani

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