Author: Lensyl Urbano

Oven calibration

Initial oven calibration curves (2009).

Catastrophic failure of one of our ovens! Last year when we started up the bread business, we bought two counter-top ovens within a couple of weeks of each other. They needed to be extra-large to fit two loaves of bread each, which made them a little hard to find. We got a EuroPro oven first, and when we found that it worked pretty well, we went back to try to get another. But just a week later, the store was out of stock and that type of oven could not be found in the city of Memphis or its environs.

Instead we got a GE model. The price was about the same, as was the capacity. We quickly realized that the GE was quite the inferior product. The temperature in the oven was never the same as what was set on the dial. Our bread supervisor at the time ran a calibration experiment, the results of which you can see above, so we still managed to use the oven. Only this year, three weeks into the term, it conked out.

We sold at least one underdone loaf before we realized what had happened, and received a detailed letter in response (which our current bread supervisor handled wonderfully in his own well worded letter). Fortunately, we have found a newer version of our EuroPro oven, which seems to work quite well.

I like the oven calibration exercise. It was a nice application of the scientific process to solve an actual problem we had with the business. Though I know it’s not quite the same, I like the idea of doing annual oven calibrations just to check the health of our equipment and help students realize that the scientific process is a powerful way of looking at the world, not just something you do in science.

Financial reports and statistics

Sally, our school’s business manager, was kind enough to come in last month to help the financial department of the student run business organize its books. It was long overdue. We’d been improving our record keeping over the last couple years, but now we have much more detailed records of our income and expenses.

This is great for a number of reasons, the first of which is that students get some good experience working with spreadsheets. We use Excel, which in my opinion is far and away Microsoft’s best product (I’ve been using OpenOffice predominantly for the last year or so because, it improved quite a bit recently, and I’m a glutton for certain kinds of punishment.) I’ve been surprised by how many students get into college unable to do basic tables and charts, but hopefully this is changing.

The second reason is that the Finance committee can now use the data to give regular reports; income, expenses, profit, loss, all on a weekly basis. I expect the Bread division to benefit the most, since it has regular income and expenses, offering students frequent feedback on their progress. We’re now collecting a long-term, time-series data-set that will be very nice when we get to working on statistics in math later on.

In fact, we should be able to use this data to make simple financial projections. Linear projections of how much money we’ll have for our end-of-year trip will tie into algebra quite nicely, and, if we’re feeling ambitious, we can also get into linear regressions and the wave-like properties of the time series of data.

Standards, scope and sequence

Curriculum alignment graphic. Still very much a work in progress.

The Montessori middle school curriculum we use is designed to meet the Texas state standards, so there are some interesting lessons about Texas history that I’ve had to drop or adapt, and some other topics that needed to be supplemented or replaced. Trying to represent this all in the same place has been quite the challenge. I’ve been working on the graphic above for some time.

The graphic is set up with the Tennessee Department of Education’s standards in mind, but I’m using the free, mind-mapping software, VUE, to make it easily adaptable. This way I can update any small annual changes fairly fluidly, and plug in the national standards when I get around to it. Aligning all the standards can be a bit of a pain, because the graphic really should be broken down to show the individual assignments that meet specific standards, but the figure is busy enough as it is.

In case it might be useful to anyone else, and so I can keep track of it myself, in addition to the image above I’m also posting a pdf version as well as Full-overview.vue here, with the strong caveat that it is very much a work in progress.

Jobs market update

Classroom jobs market trading board.

I pitched the jobs trading idea to the class today over lunch. Ever since our first immersion, when couldn’t figure out how to sit down together for dinner, I’ve been working on getting them to think of mealtimes as a time for community building. Yesterday and today we had group discussions while we ate, which actually worked quite well for having a civil conversation.

I set up the basic jobs table for the next two weeks and established that the jobs supervisor would be the only person with the ability to authorize trades. We’re using the whiteboard above, which I like because it’s a bit like the Iraqi stock exchange right after the invasion.

My biggest concern was about how students would try to game the system. Fortunately, before I could even finish my pitch one student offered another a dollar to do their job for them, so I could go into great, loving detail that the rule is that the only commodity that can be traded are the jobs.

So we’ll see what happens. The market had its first trade this afternoon, though it might have just been for the novelty of the thing. It did become apparent that we need to post the details of the classroom jobs somewhere since the students are not yet familiar with the intricacies of each job. I plan on keeping track of the market volume to see how things develop. It would probably be interesting to survey the students in about a month to see what they think about the market, and if it achieved its objectives of making the classroom cleanup more efficient and enjoyable.

More mitosis resources

Onion root tip cells, with chromosomes stained to show cells in different stages of mitosis. Image from uafcde.

One of our small group activities is to look at mitosis in onion cells. Anna Clarke, recommended the University of Arizona site which has an Online Onion Root Tips activity for those without access to the slides or microscope. It also provides a good review even if you do have those resources. Dr. Paul’s page on onion cell division is a good supplement to the Arizona site because of its great cell images.

If you’re feeling ambitious and want students to make their own slides, you can try the SAPS page on Mitosis in root tips.

Mitosis resources

Our assignments for natural world usually combine some reading and some type of activity, but all the short video clips available online are a great resource, so I’ve been adding them to the studyguides as I find them.

The above two-minute, cell division video is a great example. Mitosis is a process, so it makes a lot of sense showing it as an animation, rather than discrete pictures in a figure. The video makes deciphering what’s going on in the diagram in the textbook a whole lot easier to understand, while the textbook diagram fills in the detail so the whole thing makes more sense.

There are also a number of useful interactive animations online. John Kyrk’s is quite nice. I like how the CellsAlive animal cell mitosis page lets you step through each frame in the animation.

Anaphase: Lengthening microtubules push the two sets of chromosomes further apart. (from Wikipedia)

Wikipedia, as is so often the case, also has some nice images.

Spore: Lamarkian in the subtexts

Playing Spore.

During our last immersion, one of my students brought in the computer game, Spore. Although the game subtly indicates that it’s your progeny that gains evolutionary advances, the fact that you get to choose what you want (extra horns, poison sacks), and the fact that you can see yourself (or do I mean your creature) evolve on the screen, really smacks of Lamarckism. While it’s appealing to think, like Lamark, that you can pass on traits gained during your lifetime to your kids, despite some fascinating new research, that’s just not how evolution works.

Evolution is not directed by the organism but by their environment. In a population of organisms of any particular species there is going to be some variability due to simple, random genetic mutation. Some lucky members of the species might have a mutation that makes their muscles better at burning oxygen during sprints, making them able to run faster to get away from the lions. So they survive and pass their genes on, with their genetic mutation. Of course, if lions become extinct (disease maybe) then this trait may no longer be beneficial and something else, like maybe intelligence, would be selected for.

The game can capture your interest, however, so I’ve asked the student who brought in the game to come up with a presentation explaining why it would be useful to have the game in the classroom. I am, after all, not instinctively opposed to using computer games in class. I’m really curious to see what this game looks like from the student’s point of view.