2008-08-01

TAU, old: calibrating a spectroscope

This is an important lesson on why asking questions is important. You know all these people who are never afraid to make idiots of themselves for the sake of others? YM was one of them.

Sergei, the legendary labA guide, was by no means a brilliant dude. An earlier argument about how capacitor behaves at low and at high frequencies was stopped by "Stop thinking, you are not supposed to be thinking. You are supposed to be doing an experiment."

The announcement was "today, we are going to calibrate a spectroscope, by using a photoelectric chamber." This is how a 30-min instruction started. Okay then. Photoelectric effect is sensitive to light wavelength. Hmm.. Let's hear more, I thought.

While the instruction continues, everybody looks stupidified linearly, at precisely constant rate. Nobody asks questions. Some hoping it will get clear in just a moment, others planning to rely on their partner.

"This is a spectroscope" says S pointing to a black box. "And here it has an opening for the light." And this (round on a stick) is a photoelectric chamber.... Hmm.. we heard about internal photoelectric effect in semiconductor films. But.. but what?!

Now comes in a huge mess of wires and a digital HP oscilloscope and a demo about its time measurement features... what the hell...

Heck, a spectroscope is an accurate device. A photoelectric effect is by no means a precise thing. This candy stick and the box don't look like anything to match their names. "And this knob here in the back (of the spectroscope) adjusts the light frequency.." "and you can also switch unit scales!!" MAA?

Some kept wondering what have they missed and whether it was in the beginning of the explanation, or maybe they should have listened what their mother was telling them when they were young, but physics at TAU clearly started looked like a wrong choice for their small brain. The deeper into the swamp, the stupider any possible question would look. This time Sergei seemed like he knew perfectly what he was talking about. Some students made smart faces to pretend like they grasped some of his words. This collective stupidity added to the collective confusion.

Shortly the instruction was over. "Now you can proceed to make an experiment," said S, "are there any questions?". A long dramatic pause. Nobody moves.

YM stands up.
- "Yes, " he says. "Please explain it all from the beginning. I didn't understand anything.."
People seen starting to breeze as in "god bless YM".
S, angrily: "What didn't you understand?"
Y: "nothing. What do you mean by calibrating a spectroscope with a photoelectric chamber?"
S: "oh.. have I said 'spectroscope'?"
Y: "yes, you did. 20 times"
S: "It's a stroboscope!"
PPL: "omg..."
S: "Ooops. sorry. OKay, now please proceed to do the experiment.."
Y: "No. Now you explain it all from the beginning."

-EOI-

The "photoelectric chamber" was just a single-bit light detecting transistor. Lab purpose was to demonstrate a digital oscilloscope, using it to measure pulse frequency.

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