Tuesday, September 18, 2007

Constants Aren't Constant, Apparently

So it's really late (4:20am, to be exact), and I am still working on a problem set which I swore-- after reading a few questions-- was going to take me no more than 6 hours to complete. I was way off, and now I'm even more off, because I am taking a break to rant about it on the Internets.

Of course I should have started my work earlier (not the day before it was due as is familiar in my usual routine), but it just looked so easy. And of course the usual excuses (not to mention serious ADD) outweighed my desire to get my work done early this particular week. Those excuses included a move to Southern California, a wine-tasting trip with some newly acquired friends, and the need to help my artistically-challenged boyfriend map out dungeons with an algorithm we invented while playing Phantasy Star 2-- an awesome RPG made for Sega Genesis. (If you enjoy RPGs and you missed this one in the 90s, you should seriously download it. It has the best music ever, too.)

Right, so back to the problem set. It's for one of my courses called Semiconductor Device Fabrication, or something. Basically I learn how microprocessors (and other devices) are built, which includes their physics, technological advancements, and the mechanical/electrochemical processes by which they are made. This is really cool stuff-- and it can be complicated at times-- but really, the problems looked so simple. They were much simpler than anything I was ever required to solve as an Astrophysics major, anyway.

And I was right-- the problems were SO easy. But the rub is that I was given about 1/3 the information required in order to solve them. There was a serious lack of constants, conversion factors, atomic data, and sometimes entire equations. This doesn't sound terrible, but believe me, it is. And I'm one of those people that knows off the top of my head things like, one electron-Volt is equal to 1.602 x 10^-19 Joules . Figuring out constants is not something which is normally a challenge.

I have wasted approximately 8.73 (+/- 0.6) hours of my time looking up this missing information on the Internets. Obscure physical constants are not terribly easy to find on the web, nor do they often appear in the units you desire them to. A simple search for "So-and-So's Constant", or "Blah Blah Equation", will often lead to a plethora of high school science experiment websites, none of which can provide me with reliable information.

A Wikipedia search yields the exact opposite result: topics on Chemistry or Physics are written by know-it-all asshats who can't wait to shout from the rooftops everything they just learned in last week's lecture, so they spew it all onto the Internet in a format not at all dissimilar to that found in their textbooks. While the page-long paragraphs of facts they display are usually quite accurate, there is not one iota of useful information contained in them.

I searched for the equivalent units of amu (atomic mass unit)-- because (*gasp*) I don't remember my high school chemistry unit conversions-- for nearly an hour, because 3 different websites gave me 3 different (and yes, conflicting) definitions. No, this information is not in the course text book. I realize it would not be such a big deal to look this one detail up on the Internet-- but the problem was that there were literally 297 of these little details to look up. Seriously, why is there not a sheet with useful data on it!? I realize this is a graduate class, but having to research constants should not be impeding me from doing the actual work! Sssssss.

The sad thing is that I have at least a dozen wonderful Physics books, each with a plethora of this sort of information contained in neat little tables in Appendices A through C, or sometimes even as far as D. Those books are in boxes which weigh 8 tons each, and are all stacked on top of one another, waiting to move from the sublet to the new apartment. I think this coming week, I will be doing some temporary unpacking.

In addition to the sheer lack of necessary information, some of the questions are just ridiculous. One of the problems from my textbook asks me to "Find the resistivity of pure-silicon at temperatures of 77K, 300K, and 1000K." FIND? Don't you mean calculate? Surely there must be a temperature-dependent equation for resistivity somewhere in the text. No, there was not, nor am I aware of any such equation which doesn't go way beyond the bounds of this course. After scrutinizing the text for several minutes (it was like motherfucking Where's Waldo), I managed to "find" one value for resistivity, which corresponded to 300K, but no where in sight were the values for the other two temperatures. There was also no graph or any other piece of information from which I could derive a relationship or make any type of inference as to the values of the mystery resistivities. My final answer was that the resistivity at 77K was greater than that at 300K, while the value at 1000K was smaller. True, though not so much accurate.

I'm currently working on a problem which features an equation that, based on an example given in lecture, does not equal itself. The units are correct, but the numbers (or clearly something else) are not.

All I can think about is wine tasting in Santa Barbara later today. I think there's a good chance I'll be passing out in a vineyard.


Hilary said...

Constants aren't constant is much like "Freedom isn't free". They both cost folks like you and me. But apparently, especially you.

A Margarita said...

Wow, sounds tough. Most of that went over my head, lol but it sounds like you have a handle on it. The wine might inspire you ;)