The story of the most epic pset ever by Laura N. '09

This semester I’m taking a class called “Sustainable Energy,” and so far, it’s pretty awesome. It’s one of the few classes where I really feel like I’m learning a lot. I mean, I’m sure I learned a lot in 2.005 but it’s hard to feel like you’re learning, you know? You try doing a problem that requires you to use the heat equation and see if you finish feeling less confused than you started.

But in Sustainable Energy we learn lots of actual, concrete stuff in every lecture. So every Tuesday and Thursday I leave class thinking, “So that’s how carbon sequestration works,” and feeling all enlightened and such. Part of this is because the class is HUGE in scope. We tackle the energy problem from what seems like every possible angle- economics, engineering, science, politics, nuclear, mechanical, physical, electrical, you name it.

To illustrate this, I documented some of the sleepless night I spent the other day working on what was quite possibly the most epic pset of all time.

It started out with a pair of daunting circuit problems which I probably would have breezed through back in the Stone Age when I was taking 8.02 (seriously, I feel so old now it’s not even funny) but were definitely beyond the rusty remains of my E&M skills.

After awhile I visited the handy “Conner 2 library” (fancy name for a bookcase in the floor lounge where people stash old textbooks they don’t want or need anymore for anyone on the floor to use) and grabbed a copy of the 8.02 course notes. What’s impedance again? And inductance…is that thing…it’s like the opposite of capacitance, so they get all wavy in an RLC circuit. (Believe it or not, freshman year I actually went back to my high school and successfully taught the lesson in RLC circuits to the seniors in AP Physics. I must be getting senile in my old age.) The textbook was not very helpful.

I eventually had to give up on the circuit problem for a little while, even if just to give my mind a break. Problem 2 was about carbon dioxide emissions. If there are 0.9 hydrogen atoms per one carbon atom in every molecule of coal, and 2 oxygen atoms per one carbon atom in carbon dioxide (well, duh) then how much CO2 is produced by burning one kilogram of coal? I had a feeling this was some kind of chemistry problem, but I shoved that thought to the dusty back corner of my mind, right next to the word “stoichiometry.” I just made up some ratios that made sense and went on with my life.

But then I checked the forum on the course website (MIT has a system called “Stellar,” which is sort of like an automatically generated website that professors and TAs can use to post materials for their classes) where the course TA had posted some answers to questions people had been asking about Problem 2…and they were all talking about molar mass. I’m going to be honest with you, I cannot for the life of me remember the difference between atomic mass, atomic number, atomic weight, molar mass…I mean, I used to know them all at one point but…that was also back in the Stone Age. So I headed back to the Conner 2 library and found someone’s used copy of the 5.111 (basic freshman chem) textbook. I could not find anything about molar mass in it. I was either really sleep-deprived by this point, or had managed to pick up practice problem book or something weird that didn’t actually explain anything. Back to the library to trade it for someone’s old 3.091 (alternate “flavor” of freshman chem) textbook. Right before the section in stoichiometry was a section on molar mass. Hey, the 3.091 textbook is organized just like that dusty corner of my mind! By this point the kitchen table had been consumed by my psetting.

I read some more about this “molar mass” thing and just ended up feeling more confused. Basically, the moral of this story is that I forgot everything I learned freshman year. I turned to Problem 3 for inspiration. The problem statement came complete with a full chemical equation, which was totally not helping. Thankfully, Adelaide appeared soon after this, and graciously attempted to teach me something I swear I mastered in my junior year of high school. (Ask Ms. Lyons. Seriously!)

Me: “But…but…why can’t you just do it the way I did, with ratios?”
Adelaide: “Well, you can, this just makes it easier.”
Me: “…okay this is why I’m a physics person.”

Alright, time for Problem 4. Problem 4 was an essay. I’m not kidding! Write two pages about fuels derived from biomass and carbon sequestration and whether you think these are sustainable technologies. This pset has everything. Except like, some nuclear problem.

Oh wait, that was Problem 5.

Okay, the essay is done, Problem 5 is actually super easy despite being in the one topic that I didn’t learn 3 times already during my academic career, and now, that final moment of absolute blissful satisfaction: when you take out the stapler and feel satisfying clunk of attaching all of the pages together in a neat pile, ready for submission.