Saturday, June 1, 2013

DUCKLINGS (or: TA-ing undergrad fluid mechanics)

I was signed up to take a teaching seminar this past semester, of the "read papers on teaching theory and discuss" variety. Within the first week, I dropped it.

Why, you ask? Well, it might have been a useful class. But there is nothing like learning from experience. And this past semester, I was given the chance to TA for one of the best professors I had as an undergraduate. There was no way I was turning down this offer.

Not to say I was not hesitant to take on this responsibility. The TA before me was essentially a superstar, which meant I had a lot to live up to. I was also still taking my own classes and trying to make progress on my research in the same semester. Your typical, daunting semester in grad school, right?

But I digress.

This blog post is going up now, of all times, for two reasons.

One: subject evaluations just came out, and apparently my ducklings appreciated my efforts to help them learn regardless of how dubious those efforts seemed to me.

Two: I am finally in a position to reflect on the semester. The class is over, my other classes are over, and my research requires a couple of long simulations that leave me thumb-twiddling for at least ten minutes at a time.

A caution, however. As I said, I chose the practical instead of the theoretical when it came to teaching students this past semester. My experience is, well, mine, and may not match popular wisdom about education these days. Feel free to draw your own conclusions.

So what is an undergrad fluid mechanics course, and what exactly does a TA do for this class?

My responsibilities were clear from the beginning. I was in charge of constructing the problem sets, checking the work of the problem set graders, holding office hours for the students, and leading two 2hr recitations a week. I was also expected to be at every lecture.

I expanded on this list based on my experience in this class as an undergrad. I gave the students my email and promised to answer any questions they had about the course as quickly as possible. I occasionally held extra office hours on weekends if I thought the students needed it. I also was available to meet with students one-on-one if they had conflicts with my office hours.

The structure for the class, on top of all of this, was straightforward: three 1hr lectures a week, two 2hr recitations at the end of the week, and two midday office hours before the recitations.

And the students learned fluid mechanics. I'm not going to tell you exactly what about fluid mechanics they learned, because I'd need about three months worth of a blog post. And I am done with this whole teaching thing for the foreseeable future. I can recommend textbooks if you are interested, though. Just ask!

In the meantime, the important stuff.

What did I learn from teaching students?

0) They are ducklings, not students. It's an endearing term a friend of mine began using for his mechanical engineering students, and it definitely makes these guys easier to deal with.

1) I am a nice TA. An unusually nice TA. Apparently offering extra weekend office hours and being incredibly communicable by email is not standard. At the time, I did not think I was overly available to my students; I had my own classes and research to take care of. However, I made an effort to act like the TA I would want to have. I'd like to think I have an understanding of the anxieties that can be spawned by this particular class; I worked to minimize them for my ducklings.

They definitely appreciated this. A lot of the comments I got on my evaluations appreciated my quick response to emails and willingness to meet outside of class.

Why isn't this a universal practice? There is definitely a limit to how available a TA should be, but why aren't more TA's responsive with email? It is the age of internet communication; office hours alone are not sufficient to answer all student's questions.

2) Office hours during the day are useless. I only had mine scheduled as such at the behest of my professor. But no one comes to office hours during lunch. I wish I could have changed them. Evening or weekends would be much better.(If you are a grad student reading this, don't even pretend you have a life which would make this kind of scheduling hard. You are a grad student. Get a life after you finish your PhD).

3) I am very empathetic with my students. Oftentimes this meant my professor had to reign me in -- I tried to self-regulate my availability and my willingness to do whatever I could for them to help them learn, but occasionally my professor had to flat-out forbid me from going overboard.
I probably should have self-scheduled time for individual meetings with students. Regular time, unchanged from week to week. It would have kept me a bit more reasonable with the whole "meet with me whenever" business.

4) Students are ducklings, but not children. They can think for themselves, and they have to put significant effort into the class to get anything out of it.
This should be made as clear as possible from the beginning. Those who do not get the message...actually, this is a tough one for me. I was never clear how to treat the students who blatantly did not try to understand the class material. I wanted to shake them back and forth, as if this would impart to them that they needed to give something to get something out of the class. But I had the oddest feeling that this would have been inappropriate. Just a little.

Any thoughts on this would be most appreciated--the "lazy duckling" is something I struggled with all semester.

5) Do not allow laptops in lecture. Ever. They just distract students.

6) Traditional lecture format can be fine, but it needs to be kept short. Do not go over time every damn lecture. My professor did this a lot, and you could just see the ducklings' switch off the second the clock struck noon and they had to be at their next class.

7) The absolutely most helpful thing a TA can do for their students is act like a translator for the professor. Pare the lectures down to the bare essentials, give students a framework for the concepts learned in class. This was the goal of my recitations, and according to my ducklings it worked well.

One duckling commented that they would have appreciated it if I had typed up the frameworks presented in recitation, but I figured that this was the benefit of actually coming to recitation. If you were fine with the material, you could skip the recitation. If you were not, you got something extra out of it.

And that is it. The entire semester, boiled down into seven key lessons. No psycho-analysis here, no suggestions on the best teaching style. Just an idea of what a TA should be doing. My personal teaching style, mind you, is something I have never carefully examined (no one has ever filmed me giving a recitation, for instance). I should probably do that sometime soon. But the general approach, I think, is to be genial and friendly with the students during class. Speak loudly and clearly, have your talk organized, toss in a couple of jokes to wake people up, do not be afraid to cold-call, and write legibly on the board.

I will miss my ducklings. They were all wonderfully intelligent and hard-working (well, for the most part ^^). I am glad I got the chance to teach them this semester, and I hope they got something from it.

Sunday, March 24, 2013

Steel Bridges -- the weird way

I am working on two things at the moment. One is a coastal wave model that often makes me feel like a blind astronomer. When it works, it is wonderful, but when it doesn't I spend weeks poking around trying to figure out why it is hiccupping. Akin to sticking your hand in a black box of spagetti, trying to ferret out the one strand of angel hair pasta.

The other is something I do in my spare time, when it exists. It has absolutely nothing to do with waves and fluid mechanics, so I don't think it will be featured in this blog just yet. I need to be more comfortable with my progress on it, anyway.

However, seeing as it is pasta-black-box time in my research once again, I think I will take this opportunity to write about something else completely unrelated to coastal research--a finished project I constructed in my senior year.

I built a steel-chain compression walking bridge.

It was one of those school projects which could have been made to meet spec with some 2x4's and a couple of screws, easy. But my senior design class was all about making things harder for no good reason.

So, yes, we could have made an arch bridge out of wood. And it would have worked just fine, spanning 10 feet and being over 3 ft off the ground with ease. But why do that when you can do something completely crazy, and build an arch bridge out of traditional tension elements?

Because learning to weld. And making crazy mechanisms to avoid as many calculations as possible.

In short, because fun.

Prototyping. With paperclips.

Basically, the original idea was to hang the chain and weld it into place, capturing a natural and perfect arch shape.

Compression testing for different link sizes.

Turns out hanging over ten feet of chain in the lab and leaving it until we felt like welding was not going to be an option. So we decided to weld individual segments straight and then piece them together. 

Our janky weld set-up. But, hey, behind the appropriate screen!

Partly welded chain, partly not. We left one link free for each straight segment, so we could...

Hang the chain length between a ladder and a doorframe and weld each joint together? Not planned at the last minute. Nope.

Securing the ladder. Steel chain is heavy, man.

This actually was not overkill. By a long shot.

At some point we had to deal with the deck. Unlike the chain arch, this took all of two hours. I am really comfortable working with wood thanks to non-academic projects in undergrad.

The two completed arches! Now to put everything together...

We needed to support the endload somehow. So we were lazy -- well, mainly pressed for time -- an basically tacked on some 4x4's on the ends

Which made the arch structure completely useless. See? I said at the beginning that the design specs could be met with nothing more than some wood and screws. 

Having proved that to ourselves, we decided we might as well be all in or nothing. So we went back to weld eight more compressive elements for the ends of the bridge and to brace the joints of each arch.It meant several more hours in lab, and lots of time readjusting the design and angles of every new element, but it was worth it.

Testing day. We definitely had the easiest set-up. Just planted the thing on the ground.

Loading the bridge with concrete blocks. The goal was 2000 lbs without failure.

 And, almost passed the 2000 lb distributed load test with ease. Less than an 1/8'' deflection. Barely measurable.

Also, as it turns out, holds five point loads quite nicely. 

I think the bridge is currently the desk of some civil engineering professor. Rather fitting.

The bridge testing day was by far one of the best days my senior year. Building something is an accomplishment. I realized that day that all of the hard work, backtracking, and flexibility needed to complete a project well was worth the trouble. You cannot schedule everything ahead of time, for certain (as much as I would like to pretend otherwise).

Also, I realize that mechanical engineering majors must have all of the fun all of the time, if they get to build things their entire undergraduate career. I take small satisfaction in the thought that they will not be building bridges, though--and certainly not ones that have no business existing.

Thursday, March 14, 2013

Yup, I'm still alive

If anyone has been reading this, you may have noticed that I stopped updating early last semester (I'm a grad student, I think in terms of academic years).

This is not by accident. Semesters eat my life, just in general. It is difficult to justify doing "frivolous" things that my advisor or professors will never see. Heck, I'm still shocked /you/ are reading this.

However, that is no excuse for my failure to update during winter break, or even before classes in January. So, the way I see it, you are owed at least two more entries to this thing before summer begins.

Before I officially begin either of those entries, however, I wanted to explain the real reason I have not been keeping up with this blog, especially during the winter. Last semester, a lot of things changed for me. I stayed in roughly the same geographic location, but I became a new kind of student with different responsibilities and a wildly different living situation.

My world basically flipped upside down without my approval. Adjusting takes time, and doing good work while adjusting is completely possible (especially if you are as stubborn as I am), but takes a nontrivial amount of effort. Occasionally this means ignoring things. Occasionally it means sacrificing things. But it had to happen, and I am hopefully close to righting my world (or reorienting what I consider to be "up"...metaphorical gravity is a funny thing).

Additionally, I realized that I did not feel like chronicaling old projects in detail on this thing. It is a good exercise, sure, but that's why I have a lab notebook. I find it dull, and I can only imagine how a reader feels about it.

Therefore, I plan to revive this blog during the spring semester in a tentatively new direction. Excrutiatingly detailed projects, written like a science paper, just won't cut it anymore. Instead, I have a couple of new topics I hope to get in written form in the near future--/concise/ written form, mind you.

The candidates are:

- welded chain steel bridge (chain as a compressive element! The one project my senior year I felt proud of)

- how to choose an advisor (part II! With nuts!)

- waxing eloquently about the oceans (I gave two talks last semester about this, and only further realized my passion for keeping our world in some semblance of working order)

- Teaching (fluid mechanics, what else? I have ducklings now!)

- Grad projects (?? Let us be honest, I have no idea how much of what I currently do can be published casually in a blog. Name of the game in science).

So. Hold me to at least two of the above topics and I will consider myself to have made up for December and January.

In the meantime. Things change. Hence the title of this blog ("fluid" archive. Get it? Get it? Poke.) I'll try to keep this at least moderately active depsite all of the craziness of real life.