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inbabylontheywept · 10 months

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Kevin vs. Quantum Mechanics

This is an autobiographical piece. Names have been changed for anonymity, but it's otherwise left be. ---

The class's first suspicion of Kevin was that he had, somehow, cheated his way up to this course. He just seemed perpetually confused, and strangely antagonistic of the professor. The weirdest example of this was when he asked what an ion was (in a third year EE class?), and was informed that it referred to any positively or negatively charged particle. It would have been strange enough to ask, but his reply of "Either? That doesn't sound right" sealed him in as a well known character in the class of 19 people.

The real tipping point in our perception of him during a lecture where the professor mentioned practical uses for a neutron beam, and Kevin asked if a beam could be made out of some other neutral material. When asked "Like what?", he replied "An atom with all of its electrons removed." When we pointed out that the protons would make that abomination extremely positively charged, he just replied with "So what if we removed those too?" and then was baffled when we informed him that would just be neutrons.

That's high school level chemistry. Not knowing it was so incredibly strange that I felt like something was off, so I asked him if he'd like to grab lunch. He accepted, we chatted, and I finally began to get a sense of his origin story.

See, Kevin wasn't a junior/senior electrical engineer like the rest of us. Kevin was, in fact, three notable things: A business major, a sophomore, and a hardcore Catholic. All three of those are essential to understanding his scenario.

What had begun all of this was actually a conflict with Kevin and his roommate. Kevin frequently had his fundamental belief in Absolute Good, Absolute Bad, and Absolute Anything pushed back on by his roommate, who was in STEM. Said roommate kept invoking quantum mechanics as his proof against Absolute Knowledge. Kevin was tired of having something that he didn't understand thrown at his convictions, so he decided to take a quantum course to settle things once and for all.

Despite not having any of the pre-reqs.

He'd actually tried to take quantum for physicists first, but the school's physics department wouldn't let him. It's actually pretty strictly regulated, because it is a mandatory class for physics majors. However, because quantum is not mandatory for electrical engineers, there aren't really any built in requirements for the class. It's just assumed that nobody would actually try to take it until their third year because doing so would the be the mental equivalent to slamming your nuts in the car door. Just, pure suffering for no good reason.

Apparently, the counselors had tried to talk him out of it, but if Kevin was one thing, it was stubborn. He'd actually had to sign some papers basically saying "I was warned that this is incredibly stupid, but I refused to listen" in order to take the class.

He was actually pretty nice, if currently unaware of how bad he'd just fucked up. I paid for the lunch, wished him the best, and reported back to the class discord. We'd all been curious about this guy's story, but now that I had the truth, I could share it with the world.

Feelings were mixed. Some people thought he was going to drop out any minute now. Others thought that he wouldn't, be also that convincing him to drop now, while he still could, was the only ethical thing. Others figured that a policy of non-interference was best: The counselors couldn't dissuade him, and if we tried to do the same, he'd probably just think it was STEM elitism trying to guard its little clubhouse. He'd figure out how hard things were, or he'd fail. Either way, it would help him learn more about the world.

We wound up taking the approach of non-interference. If nothing else, understanding his origins gave us more patience when he asked bizarre questions. He wasn't trying to waste our time, he was just trying to cram three years of pre-reqs into a one semester course. He did get a little bit combative sometimes, and we could tell that he was really wracking his brain to try and find some sort of contradiction or error that he could use to bring the whole thing down, but he never could.

First test came by, and he bombed it. Completely unprepared. He'd taken Calc I, but he didn't know how to do integrals yet (that was Calc II). Worse, he was far past the drop date. I imagine most people in his shoes would've stopped struggling. They'd realize they were fucked and just let themselves fail, at least salvaging their other classes grades in the process. Why waste resources on an unwinnable battle?

Kevin never asked questions like that. If he was stupid enough to try it, he was stupid enough to finish it. God bless him.

He invited me to lunch after the test and said that the class was more fascinating than he'd ever imagined, but he didn't know if he'd be able to pass it. He asked if I could help, and I said...maybe. I brought the request to the discord, and from the eight people there I got three volunteers who admired this dork's tenacity. He was in over his head, miles beneath the surface, but his fighting spirit was fucking glorious. If he was willing to go down swinging, we were willing to bust our asses trying to get him caught up.

Some of the stuff was just extra homework we gave to the guy. We told him he needed to learn integrals, stat. We sent him some copies of basic software that can be used to teach the basics of linear circuit equations, and he practiced that game like it was HALO. Just, hours sunk into it. Absolutely godlike.

He was still scrabbling for air at just the surface level of the class, but he'd gone from abysmal failure to lingering on the boundary between life and death. Other people in the class started to learn about Kevin's origin story, and our little circle of four volunteer tutors grew to six. Every day, he had someone trying to help him either catch up in some way, or finish that week's homework. He'd gone from being seen as a nuisance that wasted class time to the underdog mascot.

He was getting twelve hours of personal tutoring a week, on top of three hours of classes, on top of six hours of office hours, on top of the coursework. I don't think it's an exaggeration to say that this kid was doing 40 hours a week just trying to pass this one single class.

Second test comes around and he gets a 60. He's ecstatic. We're ecstatic. Kid's too young to take out drinking so we just order a pizza and cheer like he just won gold at the Olympics.

After that second test, things hit another tipping point. With so much catch-up under his belt, he was able to focus a lot more on the actual material for the class. A borderline cinematic moment happened when I was trying to get ahead on the homework so that I could put more hours in on my senior project. Nobody else had finished it yet because it wasn't due for another week, so the specifics of the problem I was working on were still a mystery. I went to the professor's office hours and get some pointers, but he wasn't willing to give good hints when the HW wasn't due for another week or so. He said I still had time to think about it, which was true, but I wanted to be able to think about other things. Kevin had watched the whole conversation, waiting for his turn to ask the professor more simple questions, but when I left I got a text from him telling me to hop on zoom.

Kevin had finished it earlier, because Kevin started all of his homework the moment it was assigned. He needed to, in order to make sure that he could get it done on time. He'd finished it the day before, and was able to walk me through it.

From student, to teacher. I'm not exaggerating when I say that he probably saved me eight hours on that assignment. I could've kissed him.

A month or two later, we took the final. As soon as we were done, we six asked Kevin how he did. He was nervous, there was so much new material for him in this class that his retention hadn't been great. Us six were also a little stressed: We were going to pass the class, but the final was hard.

We waited for the results.

And waited. And waited.

Finally, the scores were posted as a table, curve included. From our class of 19 people, 4 withdrew within the deadline, 4 failed, 1 got a C, 8 got B's, and 2 got A's. We could see that the curve for a C was set at 59.2% overall.

We called Kevin. He was crying. End score, 59.2%. Teacher curved the C exactly to his score.

It was a week into winter break so we couldn't gather the forces around for a party like last time, but we were all losing our shit. Kevin was losing his shit. He couldn't believe how stupid he was to try this course, he couldn't believe that six people busted their ass just to make sure he didn't die, and he couldn't believe that the professor basically just passed him out of sheer effort alone.

He said it was the stupidest thing he'd ever done, and while I doubt that, it was outrageously stupid. And yet, I've never been so invested in a fellow student before. I'm prouder of Kevin's C than I am of my own B. I was walking on sunshine for weeks after that. In theory, my senior project was building a functioning washing machine, but in practice, in my heart, it was helping Kevin pass Intro to Quantum for Electrical Engineers.

(And as an epilogue: No, he did not renounce Catholicism and become an atheist like his roommate had hoped. He did walk out changed. I think that being that wrong about something, and realizing it, was a pivotal moment for him. It's hard to be dogmatic once you realize that a lifetime of being wrong feels exactly like a lifetime of being right, right up until the last two seconds of it.)

#writing #Kevin #electrical engineering #college #memoir #biography #college stories #group project #quantum physics #senior project #people are awesome

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inbabylontheywept · 12 days

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A Short Essay on Signal Reflections

The essay nobody asked for, but I've been reading about for around a week, and now can explain very easily and intuitively.

When electricity flows from a region with low impedance to a region with high impedance, a reflection of the signal passes back up the cable towards the source. This tends to make the most intuitive sense to people - after all, the high impedance region is easy to imagine as a traffic jam, and the ripple going up the line is just all the electrons having to slam their brakes. We've seen this before.

However, you get an identical ripple when going from a region with high impedance to a region with low impedance, which kind of mangles that analogy. You don't see traffic jams in regions where the speed limit goes up, just in places where it goes down.

And so for that, we're going to have to break the signal into two parts.

V=IR is bread and butter, but nobody accounts for those in time. Everyone does DC steady state analysis, and this is slightly weirder. So in a line with low impedance to high, you just look at how much V (voltage) you need to push the same amount of current (I). Since R is getting bigger, you now run out of voltage before you run out of current. So all the voltage gets used up, some of the current gets used up, and the current that no longer has enough voltage to get pushed forward can't enter the new material and thus bounces backwards up the line. The reverse happens with high to low. You now run out of current (I) before you run out of voltage (V) because R got smaller and energy must be conserved, so you get a voltage wave that bounces up the line. So any time R changes you have too much of either current or voltage and the extra gets sent back.

There are some weird implications to this! For example, a zero impedance ground would actually be hella noisy because it would accept 100% of the current into it, but reflect the entire voltage signal back. And an infinite impedance ground would eat the entire voltage field, but reflect 100% of the current back. An ideal ground for low noise needs to have the same impedance as the node its attached to.

#electrical engineering #engineering #signal reflection #noise reduction #a little science essay #V=IR can't explain the entire universe #but it can explain a decent amount if you can get clever with it #behold my day job

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