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I had a really interesting conversation with one of cohort the other day about a few things, primarily our students’ views of us. We got on the topic of assertion versus bitchyness. We could both act the same way, but by virtue of her being a woman, she’d be all the b-word and I’d just be called assertive because I’m a dude. This, made me laugh, cause well, I’ve heard myself be called the b-word, but well a different one. Or I’ve also been called a phallic object of sorts. Either way, I didnt let it bother me because I knew that me not giving out high grades would affect my students’ perception of me. Come on, there’s that whole thing about being sensitive to your students’ needs afterall.

I did change this year. Tremendously, actually, but I think that’s due to my situation. I was a lot more sensitive, and while I kept up the same rigorous grading standards I had before (trust me, I graded difficulty and was generally nitpicky), my students liked me this year. They thought I was fair and tough, and they felt like I actually cared about their progress, which I did. I taught fellow graduate students this year and it was a delight to have them. I got to lecture in a class, and I think the main difference between my transformation from dick to awesome TA was well, humility.

Last year, I taught undergrads. I did the whole “I am your TA, I have a degree you dont” approach, and I could see why I came off as a dick. I still did the same things I did this year, smiling, joking around, trying to be accessible, but since my students were just first year grad students, I didnt have a sense of lording over them and I think my hard grading and actually wanting people to learn were seen as passion for teaching instead of being a jerk.

Now, my students also had my friend’s class. However, more colorful things were said about her. I think the difference though is the way we might have approached the students. I told them I had office hours and to please only come then, as I had other responsibilities as well. I also told them I could be emailed if something was really needed. I also told them I would be available after lectures to discuss issues, and of course, I did what all good lecture TAs do and that’s give review sessions.

She did the same thing, but she was called things like the b-word. Her students were even well, scared of her. I felt bad for her, cause that’s how I know some of my undergrads felt about me last year. She thought it was because she was a woman in a position of power and went on about sexism in our society. She went on how it was okay cause I was a man in a position of power and how that was accepted, and while she was a woman and so she’d always be called a b.

Please, get over yourself. Some of my undergrads hated me and called me worse names. Sometimes a b is just a b. While our teaching styles were similar, our interactions with the students were different. She still went through it as a “I am the TA, you are my student. Respect mah authoritah!”.

Solid, but you’re a hardass, you didnt sing kumbaya with them or hold hands as their TA did you? Heck flipping no. I dont believe in mollycoddling (again, a mistake when it comes to teaching undergrads, they like mollycoddling), and I didnt plan on doing it with the graduate students. I also had the “I am the TA, you are my student. Respect mah authoritah!”. But the difference is I did it with a smile.

I know it sounds wierd, but every interaction with my student was with a smile. Even when inside, I was going “OMGWTFBBQ, why dont you know this?!?!?” in my head, I just smiled and apologized for /MY/ oversight and assumption that they new material. When there were mistakes on exams, I’d announce, “Oh, due to /my/ bad, problem so-and-so should have blah in addition to blah.”

Basically, I was humble. That’s difficult in grad school on some level with one-uppers and your own insecurities plaguing you, but you know what, humility is a good thing. I think I’ll stick with it for a while. Let’s see where it takes me.

Now that I’m done TAing and all my evaluations are in, I can vent a little. Back when I was a scared little undergrad, I never had a sense of entitlement for my grades. Yes, I turned in subpar and mediocre stuff. But yes, I got C and Ds for it as well. I knew that when I didnt put in the work, it would be reflected on my GPA, and that’s why my undergraduate transcript still haunts me today. As a grad student though, I worked hard and did what I could, and I earned the As that I have. For the subquality work I did do in graduate school, well the B- (and in my department, if you have two you’re automatically on academic probation) on my transcript scared the shit out of me so I put myself together.

In both of my experiences, I never thought I had deserved a good grade. When I took my advisor’s class, I didnt expect an A since I was in his group. In fact, I worked hard because I didnt want to look bad in front of my advisor. but the past two years has been a nightmare in terms of grading.

Most people I know tend to have a crappy outlook on undergrads in really high priced institutions. I didnt, as I’m a public state school kid myself, but now that I am a grad student at one of those ritzy institutions, I can sort of understand why people stereotype these undergrads the way they do.

For instance, the tuition here for undergrads is $55k a year. That was more than my four years in undergrad put together. Students here have a huge sense of entitlement, and as one instructor, who shall remain nameless told me:

“The students are consumer and you are the product. If they dont like the product, they have every right to complain.”

I worked hard as a TA damnit. I knew all my students names within the first week, I graded labs and homeworks and exams more than once, and I wanted my kids to learn. Yes, I might have been a hardass when it came to perfection and quality work, but I wanted them to see that they were capable of doing so much more. That was my first quarter. It completely backfired on me. While I was still an idealistic graduate student back then, I sent out a mid quarter evaluation with questions rating me from 1-5 and then a miscellaneous comments section. I essentially ripped off the course evaluations, cause I wanted to know how I was doing. Boy, that was a bad idea.

To this day, I still remember the response of one student.

“[whine bitch groan about how hard a grader I am]….My parents pay $$$$$$ so that I dont have a C in my intro chemistry class.”

That threw me into a conniption fit. I was pissed. I ranted and raved and punched things. And well, it’s that kind of entitlement, that sense of entitlement that pisses me off.

Then there was another student I had. She was a sorority girl. I’ve had lots of Greek kids in my classes, and they always tended to do fine, but this one was..awful. She’s a legacy student and was a constant one-upper, but never showed anything for it. She wanted to leave my lab that I was teaching 4 hours early to attend a sorority event cause she wanted to get prettied up. I said okay, but you’re going to lose this much of your grade. She threw a fit and still left.

The lab instructor for that class threw me under the bus. I got disciplined by the professors in the department, and well, that’s when I got told about the consumer nature. I feel that since students now have teaching evaluations, which are highly dependent on the grades we give them, grades have gone up.

Instead of the teacher having the power, the student feels they have the power because they somehow think our careers are in their hands, which on some level is true due to the tenuring process. All this is just messed up. And yeah..I’m annoyed. As much as I want to be a professor someday, maybe this will turn me away from it.

I’m a crystallographer in training. I love crystals. They’re pretty. Organikers love ’em too, since it’s another away asides from NMR to go through it. But asides from using SHELXTL or CRYSTALS, the math behind crystallography is lost on some people, so here’s an exercise.

So here are a bunch of pictures. To the left is an array of atoms and the right is its corresponding Fourier transform/x-ray scattering. Which ones are allowed by traditional symmetry? Yes, I’m going to talk more about crystallography, but I thought I’d put this out first…







This is a glorious feeling, kind of sort of. I finished TAing now, as I finished grading the finals for a class that I was doing. On one side, it feels good that I dont have to grade papers, hold office hours, and do all those things. But on the other hand, I enjoyed teaching the class.

I was a TA for a lecture class, and well, I liked it a lot more than having to TA for a lab. There’s a huge difference in TAing for lab and lecture. That much I learned. So, I guess here are some lessons I learned. I’m posting it more for myself. I want to become a professor, and I dont want to forget these lessons. That would be bad.

1) There are no stupid questions
There really arent. Questions need to be answered. Even the obvious questions that show the student has not paid attention should be answered or else they can screw up the experiment. Questions that seem very basic shouldnt be looked at from a “OMGWTF why dont they know this?!?!?” type angle. People come from different places and have different experiences. They may have not learned the same thing you did. Which leads to the next thing I learned…

2) Dont compare them to others
Dont compare them to yourself. That is bad. Dont compare them to previous students. That is also bad. Dont compare them to each other. That is bad. All this will lead to frustration on all parties involved and can end up in some hurt feelings if you’re not careful.

3) Dont ever hold office hours in your office
I learned this the hard way. Have someplace else. It’s also annoying that when they find your office, they feel like they can just stop by anytime. Why the hell is that anyway?

4) Dont date your students or former students
Okay, so I didnt do this, but I know people who did. It turns out to be very awkward. I know from the grad student/authority figure type, it’s way awkward, especially when it happens. So yeah..just had to get that out there. Fraternizing is frowned upon. For the love of God, wait until they graduate or something. Dont make it awkward for your friends. GEEEEEZ!

5) Dont be afraid to lay down the law
Sometimes, students are just a huge pain in the ass. They need to get checked. Badly. But at at the same time, dont be a dick about it. Grad students always complain and bitch about undergrads. I think it’s a rule or some change of mentality. I’m sure our TAs did it about us. But I digress, if you’re going to check your student, dont be a HUGE dick about it. Just be firm and fair. Not a bastard.

And those are the lessons I learned.

Thallium is awesome

Enhancement of Thermoelectric Efficiency in PbTe by Distortion of the Electronic Density of States
Joseph P. Heremans,1,2* Vladimir Jovovic,1 Eric S. Toberer,3 Ali Saramat,3 Ken Kurosaki,4 Anek Charoenphakdee,4 Shinsuke Yamanaka,4 G. Jeffrey Snyder, Science 321, 554 (2008)

The Fermi surface changes as a result of doping with Tl.
The Fermi surface changes as a result of doping with Tl.

Oh thermoelectrics, how I love thee. For those of you who dont know, thermoelectricity is the phenomenon of converting heat into electricity. For all our energy problems right now, this research could prove to be useful, if the zT (figure of merit for thermoelectrics) can break 2. I believe that a value of 3 or higher would increase the Carnot efficiency of thermoelectric (TE) modules for power generation, to make it a viable technology. I know the navy has a considerable amount invested as they’re planning to use it submarines. Automotive companies are also looking at it to make more efficient combustion engines, as the heat of the engine (around 600K) is the range where a good number of materials have a zT of around 1 or so.

I like the paper a lot. I respect the people who did it tremendously, but one of my problems is this. The parent compound is PbTe. Lead telluride. So many people do PbTe in search of better thermoelectrics. If you do a SciFinder scholar search, there are almost 100 or more PbTe based systems for thermoelectrics. As a synthetic chemist, I like new compounds. I personally believe, if we’re to break the zT barrier of 2 (in bulk materials) that we need to look at other compounds. For instance, beta-Zn4Sb3, also from the Snyder group is an amazing thermoelectric material as it’s an PGEC (phonon glass-electron crystal). Clathrates are also like that, and have the added bonus of ‘rattlers’ inside their cages to lower thermal conductivity.

PbTe is a cubic structure. Therefore, it’s Fermi surface is usually isotropic, which is, not that interesting. Tl-doping forces a distortion in the density of states by moving the Fermi level near a peak. Whenever Ef (the Fermi level) is in a high point in k-space, it’s bound to distort and usually a pseudo gap will appear (see Gruner or your condensed matter physics texts, as this is a known phenomenon on charge density waves and superconductors). This is what they basically did to PbTe. They made it’s Fermi surface interesting.

One interesting experiment that could come from this paper is a pair distribution function (PDF) analysis of the bulk. PbTe is cubic, like I said earlier, and electronic distortions still /should/ show up somehow. If you look at the PDF on this material, will the peaks show the same cubic ordering or will it change? Will the bond distances from Pb-Te be constant or will they have a greater range? Considering the size of Tl, I’m guessing there will be a greater range (duh), but it would be neat to model it experimentally.

More problems. How much better is Tl in PbTe for practical uses. Tl is notoriously toxic and the feasibility of actually using these in TE modules is IMHO, slim to nil. Let’s try to make something more environmentally friendly, or at least more environmentally neutral, so that when we save energy by being more efficient with thermoelectrics, we dont end up killing everyone around it.

However, I do like this paper in that they didnt resort to ‘low dimensionality’ or rather, nanostructuring to get it. As much as nano is a buzzword, I dont really like nano, so for that, this paper is awesome.

My first post

Wow, this is my first post and my foray into the chemical blogosphere. I decided that I might as well try this thing, since I’m working on preparing for qualifiers anyway. That means lots of reading, oh so much reading, that makes my mind boggle. Oh well, let’s do it then..