Hi blog, I’m back. I didn’t forget about you. I’ve been busy and suddenly not busy. I think I am about to be busy again.
I’m now in my second semester of teaching, encountering new problems and some surprising old ones. I’m teaching an advanced class filled with seniors and some juniors, all of whom, I keep forgetting, do not know my subject like I do, and cannot be expected to pick things up as effortlessly as I imagine they should. And they’re all actually busy, unlike the students in the gen chem class. They have research and other advanced classes.
One of my favorite things about the advanced class may be the labs. Of the six labs my mentor did, I am keeping two. I have found four more labs I like and am designing another one. They are, from what I can tell, a lot more synthesis-based, and one of them will have phosphines! I need to remember to apologize in advance.
I just had a wonderful idea for teaching the concept of the mole, relating directly to the question given above. Everyone knows that 100 pennies, 20 nickels, 10 dimes, 4 quarters, and a dollar bill all have the same buying power (though very little) but weigh different amounts. One can exchange a dollar bill for 100 pennies and have the same amount of cash, though they have different masses. It’s the same with moles. You can have a mole of water and mole of copper and they won’t have the same masses, but will have the same number of particles.
I’m slowly preparing the answer key for the 11 page review packet I gave out. Oops. I’m going to finish the first two pages and make cookies.
One of the last topics we looked at this semester was oxidation-reduction reactions, and from what I can piece together from student concerns I did a fairly bad job explaining this. I think there are several things I need to remember for when I teach this again, so I’m going to record them here, because why not? In no particular order:
I realized that a lot of students struggled to interpret structures. So in sulfuric acid, H2SO4, students might see “H2″ and not realize that these two hydrogens are not bonded to each other (oxidation state of zero) but to something else (oxidation state of +1). I should have directed students a little more at the beginning as to how to read formulas. And by beginning, I mean much sooner than looking at oxidation states.
One thing that is really on me is not always showing or writing down an oxidation state for each atom in a molecule. Since the oxidation states have to sum to the charge on the molecule, seeing the oxidation state of each atom would probably helped some students. For one student today I showed him how we can sum up the oxidation states to equal the charge of the molecule, but backwards. So if what we know is the total charge and one of the oxidation states, we can solve for x. I wish I had spent more time codifying this equation at the beginning. If we are applying our shortcuts to, let’s say CO2, we see there are two oxygens. Each has an oxidation state of -2, so altogether they are -4. Since CO2 is a neutral molecule, the oxidation state on the carbon must be such that all the oxidation states sum to zero. Well, x + -4 = 0, x = +4.
I also should have made the students do a lot more problems. On the review day, I reminded them that we already looked at oxidation states in the context of electron sharing in bonds. We drew a structure and assigned electrons to atoms based on electronegativity. The short way to get them is to say oxygen is -2, hydrogen is +1, and halides are -1 (usually) and solve other atoms from there.
The students are taking an exam tomorrow , so I guess we’ll see how it goes. For now I need to plan the final exam.
Teaching has been ambling along. I have had classes and topics which I really liked and which went very well and classes and topics about which I was unexcited and so were the students and went horribly. I did have a sort of mini breakthrough today when I realized two things. First, I probably have adhered too rigidly to my proposed schedule and not allowed myself time in class to develop some ideas. Second, I have given lectures without fully considering what it was that I wanted students to know or be able to do with an idea, and thus not building in time to work with that idea.
In the first case, I am particularly thinking about the idea of equilibrium, which I wish I had spent ten minutes or so introducing much earlier in the semester. This would have allowed me to refer back to this extraordinarily important and useful concept in later topics. In the second case, I am thinking of my brief talk on acid-base chemistry, where I lectured as to the nature of acids and bases, but the students did no calculations in class. I gave them a homework question that asked them to do a ‘titration’ and it seemed like a lot of them could do it, although come to think of it, many showed no work and probably just copied answers from the back. I am thinking about how acid-base chemistry was taught at Virginia, where far too much time is spent on it. The students learn it differently and in a more rational context than what I taught. Probably I should go over this with my own students.
Meanwhile, in baseball, Dayton Moore received an extension from the Royals. I was sitting in a bar in Bellevue when I saw the ticker message at the bottom of a college football game. I guess it’s comforting to know that one can be fantastically incompetent at one’s job and still be highly employable if one has certain knowledge.
Too bad I still have to teach lab this afternoon. It should be laid back, as the students are building models and drawing structures and looking at molecules in Spartan and drawing more structures. I don’t see a doughnut in my immediate future though, as I have been pigging out on these little brownie bites I mistakenly bought in the idea that I would feed them to my students when we celebrated Mole Day. I’m reminded of a Mike Scioscia quote on how he dealt with the stress of the Angels being awful this year, “I eat.” And me too, I guess.
Made it to fall break. The last two days of class were a struggle, even for my second section. We talked about electron configurations and why they are important and about periodic trends. I attempted to use chromium as my example for electron configuration of a transition metal, which was maybe not the best idea because chromium is unique in its configuration. So on Friday, I attempted to put it in its context by doing V and Mn as well. I think the students need to practice this a lot on Thursday. We’re taking a quiz on Friday!
Although, come to think of it, I am wondering if it would be better to hold off the quiz until the following Monday. I feel a twinge of guilt for not announcing the quiz in class (I forgot). It might actually just be better to go more slowly and practice more problems. The students took their second exam on Tuesday and I handed it back on Friday. I wanted to get that out of the way before fall break, so that by the time the students return it’ll be old news. I did meet with five students on Friday, which was refreshing.
Baseball is annoying. The St. Louis Cardinals are going to the World Series. One of the Red Sox and Tigers are going to the World Series. I guess I’ll pull for the Cardinals either way, but oh god, the Red Sox in the World Series would be so annoying.
One of them is that due to the time difference, I can’t be there often to witness the Orioles just Oriole all over themselves. Last night they played an 18 inning game and lost. They had been reduced to pitching Bud Norris, so that outcome was not all that unexpected. I can’t say I was impressed when the Orioles traded for Bud Norris and I haven’t been impressed with Bud Norris’s pitching for the Orioles since that happened. I suppose I should acknowledge that had the Orioles not acquired Bud Norris some other dicey pitcher would have been throwing last night and the outcome would have likely been the same.
Another major benefit to being on the West Coast is that now, if I wished, I actually could watch the Orioles Oriole all over themselves through the power of MLB.tv. Much as I loved living in Virginia, I could never really watch the team as I didn’t have TV and couldn’t afford to go out all the time to watch games. And up until this summer or so, this didn’t trouble me much at all. I felt like I could still be a fan, and a good one, through the Internet. Ahh, but I’d like to write about baseball and find I have nothing to say. I have nothing to pick apart because I didn’t watch the game. I only followed on Gameday and read someone else’s summary.
It occurred to me last night that this shouldn’t trouble me so far as writing goes. A lot of fans are in my position, and since no one reads this anyway, what’s the harm in writing about baseball from the perspective of a fan who doesn’t watch the games?