More thoughts on classes

More thoughts on classes Dear November, 2009: Ive reached the age when self-discoveries are easier to find than my room keys, or the chunk of free time missing from my daily agenda, or even sources of Vitamin C. To start with a simple example- I prefer my classes the way I prefer local fire departments: fast, helpful, and hosing. This semester, 8.07 (Electricity and Magnetism II) takes the proverbial cake for hopscotching around my criteria for likable classes. The first ten weeks or so straddled a slender line between geekishly fun and downright scary. On one hand, its hard to complain about a class where the professor spends 5 minutes playing the Electrostatic Video Game in the middle of his lecture slides* and then inexplicably flings his USB drive into the door using a makeshift rubber-band slingshot. (I believe he was attempting to demonstrate something about tension in field lines, but the lesson was sadly overshadowed by the fact that his USB drive looked pretty expensive.) *All seven people in attendance during this lecture burst into applause as the Positive Charge bounced off a wall, hovered in a precarious moment of unstable equilibrium, and slowly rolled into the target. It was the most breathtaking thing Id ever experienced, but only because I dont have asthma. On the other hand, the class this year was taught backwards, starting with the gnarliest subject in the entirety of 8.07: dipole radiation. Have you ever seen a dipole radiate? The thing spews out enough math to educate a third-world village. } (This is what happens when I stop taking photos. Its supposed to be a graphical representation of an oscillating dipole, alright? As I always say, MIT admissions values tolerance.) On the third hand, there was a warm and cherished moment in 8.07 when the curriculum abruptly leaped from relativistic dipole radiation to Coulombs Law. Did you know that Im probably one of the few people in human history who learned the Liv ©nardâ€"Wiechert formulation of potentials for a moving point charge before learning electrostatics? By the way, the problem set for that particular week was far more bipolar than dipolar: one question was along the lines of, “Find the force on a line charge in a uniform electric field, but use the Maxwell Stress Tensor and do a spherical integral over infinity only after converting your basis vectors into Cartesian. Also, while youre solving easy problems using the hardest method imaginable, carve a turkey using toothpicks, but only after you convert your toothpicks into a small wooden flotilla.” The next question was like, “Find the magnetic field due to a current-carrying wire. HINT: Use Amperes Law!!!11 HINT #2: The circumference of a c ircle is 2*r*pi.” “What about your other physics classes?” you ask. Well, let me prelude my good-humored kvetchfest by remarking that I have nothing to complain about and that it took quite a few yardsticks of imagination to come up with the following criticisms. Its also worth mentioning mention that Im only 35-50%* serious here: please keep in mind that all of the following are, at worst, only as mildly painful as getting punched in the kneecaps by someone wearing mittens. If you want to understand the true heartstabbing pain of MIT, you can also keep in mind that I will be repaying tuition loans for the next ten years. Now, if youll excuse me, I need to go chug a bottle of aspirin. (*Even outside of the esteemed blogging profession, Im around 55% serious at best. By “at best,” I of course mean, “at funerals.”) -8.03 (Vibrations and Waves) is a perfectly reasonable class until you realize that its full of propaganda, just like television (whose existence is due to none other than VIBRATIONS AND WAVES. Coincidence? I think not). According to 8.03, vibrations and waves created light, made the world in six days, rested on Sunday, and then invented evolution, thereby ensuring that thousands of unsuspecting children would continue to buy Pokemon cards (the most expensive of which contain reflective holograms, whose properties are due to none other than VIBRATIONS AND WAVES. Coincidence? I think not.). The first one may actually be true, but I refuse to accept the premise that waves are mankinds only remaining hope for salvation. I mean, otherwise, Barack Obama wouldnt have won the Nobel Peace Prize, right?. No OCW am I, but heres my stab at summarizing the 8.03 course material: -A wave on a spring is a wave. -A wave on a rope is a wave. -A wave in a pipe is a wave. -A wave on a transmission line is a wave. -A wave in vacuum is a wave. -A wave is also called a vibration sometimes. Did I tell you the name of this class, by the way? -8.033 (Relativity): I will heartlessly say that 8.033 makes electricity and magnetism look like clumsy squash players stumbling around in a ballroom full of elegant, waltzing kinematics, firstly because I hate playing/eating squash and secondly because I think this is some sort of metaphor or whatever. In the first half of the course, each lovely transformation and kinematics equation was tastefully attired in immaculate thought experiments before its initiation into the polite society of established physics. Yet as soon as EM clodhopped into the room, dripping with murky math and shod in raggedy logic, the exalted sophistication of relativity spiraled down the metaphorical toilet of terrible curriculum design. You could hear the flush as soon as we started transforming Coulombs Law in like 32939 different scenarios of relative motion between source charge and test charge. Introducing EM by applying the force transformation laws to Coulomb was like smearing dirt over the brilliant c onnections between EM and Special Relativity. Why not link the fields to the intrinsic properties of space and time, and then deduce how they must look to an observer moving at relativistic speeds, such as Lance Armstrong? To be fair, we probably discussed this in recitation for about 20 minutes. Lance Armstrong, that is. (Just kidding. I can assure you that we learn more about cyclic permutations than cyclist permutations in 8.033 recitation.) Also, the flavortext (yes, flavortext) on the Problem Sets is about as straightforward as the nonexistent Star Trek episode written by Richard Nixon. Example: Buckethead and Ry Cooder, two guitar masters who are completely unrelated and look nothing at all alike, meet at Antones, the famous blues club in Austin. Ry is scheduled to play the first one-hour set, with Buckethead immediately to follow. To while away the time, Buckethead hops in his motorized chicken coop and drives west at con- stant acceleration a = (5=3) ¬ £ 106 m=s2 for precisely 30 minutes (as measured by his dashboard clock) at which point he slams on the breaks, stopping the coop almost instantly, turns around, and drives back, again at constant acceleration a. After precisely one hour on his clock he arrives back at Antones, slams on the breaks again, and walks in for his set smack on time. Importantly, all along his trip, Buckethead maintained a perfect soulful C on his monster Jackson King V. Meanwhile, back at Antones, Ry plays an awesome set, closing with his classic version of Woodie Guthries Vigilante Man (as recorded on Into the Purple Valley). As the song ends, perfectly on time, he holds out the last note, keeping it ringing until Buckethead walks back in at the end of his trip. Note: some details about the real world you should neglect in solving this problem: ¬= The earth is round. Lets treat it as flat and infnite { bucketheads coop always stays in contact with the ground. ¬= Since a is roughly 20,000 g, the acceleration would crush any human inside the coop. Dont worry, Buckethead is not human. ¬= To stop the coop on a dime would require absurdly wonderful breaks. Yes, its an awesome chicken coop. Dare I venture any further comment? You know that somethings awry with your problem set when the hardest part of the question is figuring out that its a question. Anyway, the moral of the story is that physics can be crushing, but theres nothing to worry about. Buckethead is not human.