The Uses of Rare Earth Elements

Tiny quantities of dysprosium can make magnets in electric motors lighter by 90 percent, while terbium can help cut the electricity usage of lights by 80 percent.

–Lifton (2010): The Battle Over Rare Earth Metals

There has recently been a bit of a furor over the fact that, currently, China produces 90% of the world’s rare earth metals. Special properties of these elements are making them extremely important in a lot of high-tech and alternative energy technologies.

Fiber-optic cables can transmit signals over long distances because they incorporate periodically spaced lengths of erbium-doped fiber that function as laser amplifiers. Er is used in these laser repeaters, despite its high cost (~$700/kg), because it alone possesses the required optical properties.

–Haxel et al., 2005: Rare Earth Elements—Critical Resources for High Technology

The rare earths are so chemically similar that they’re lumped together in one corner of the periodic table, which is why they have not been used a lot until now. Only recently has their influence on elecromagnetic systems been discovered. Wikipedia has a good list of the elements with some of their uses.

The rare earth elements.

Many people are worried about one country controlling so much of a single resource, especially since China cut its export quotas earlier this year. Fortunately, rare earth metals are found in places other than China, and, as the demand continues to outstrip supply, it’s just a matter of time for high prices to to bring more mining and recycling projects into production.

Government and Geology in Nashville

At the capitol building in Nashville.

Earlier this spring, we had an excellent immersion trip to Nashville. The primary purpose was to visit the capitol and meet with Memphis’ State Representative Mark Kernell.

State Rep. Kernell was kind enough to spend some time answering and asking questions of our students.

But we also had time to visit the Abintra Montessori School in Nashville (who returned the visit last month), and have an excellent hike along a limestone-bedded stream in Montgomery Bell State Park. The hike, however, was not without some controversy.

Bedding planes and joints.

Shilo and Pickwick Immersion

The Shiloh National Battlefield is only a couple hours east of Memphis (or west of Nashville), and its proximity to Corinth, MS, and a state park with a hydroelectric dam, make it an excellent place for an immersion trip during the cycle when we study the U.S. Civil War and electromagnetism. Two years ago, on a couple beautiful, sunny days in the middle of spring (early April), almost on the anniversary of the battle, we made the trip.

Paleozoic (?) (250-550 million years ago) fossils from Pickwick Landing State Park.

We drove over on a Tuesday morning, and since our very nice cabins at Pickwick Landing State Park were not quite ready yet, we ate the lunch we’d brought with us at a picnic shelter on the park grounds. The choice of picnic shelter number 6 was serendipitous, because not only was it beautifully located, but just down the hill, at the edge of the water, is an excellent outcrop of fossiliferous limestone.

After unloading at the cabins, we took a short, afternoon drive to see the hydroelectric dam.

Old turbine from the hydroelectric dam.

The next morning we hiked along the Confederate line of advance during the Battle of Shiloh.

Reenacting the Confederate skirmish line at Shiloh.
Confederate or Union?

It was a relatively long hike, but useful in that it allowed students a feel at least for the scale of the battle, and the conditions the soldiers endured. There was also a nice museum at the end, with an interesting video and an excellent demonstration from one of the park rangers (you need to book an appointment ahead of time).

Finally, on Thursday morning, on our way back to Memphis, we stopped at the Civil War Interpretive Center in Corinth, Mississippi. The museum is excellent, especially the Stream of American History, which is abstract enough that it makes a great puzzle for students to figure out.

Stream of American History.

The map below shows the locations of the stops, and has links to the posts about each stop.


View Shiloh Immersion in a larger map

Block Schedules

Jenny Anderson has an interesting article on a New York school that changed from the typical 45 minute class periods to longer 130 minute “blocks” (thanks to Kara D. for pointing this one out). The whole idea of set class periods is one I’m having to get used to again as I move out of my one-teacher, one-classroom middle school at Lamplighter where time management is a lot more fluid.

Block time allows for in-depth student presentations.

Apart from Spanish class (30 minute class period), everything was pretty flexible at Lamplighter. In theory, I would have a short, spark-the-imagination type lesson at the beginning of each week for math, language, and social/physical science. Then, for the rest of the week, students would use the two hour morning and afternoon blocks to do whatever individual or group work they needed to get done.

In theory at least.

In practice, my lessons would tend to last a lot longer; I like to promote discussion, and once you get them going, adolescents often find it difficult to stop talking. So, almost inevitably, a quick review of the novel chapter they read last night would devolve into a discussion of something like Mutually Assured Destruction and continue onto the potential for accelerated evolution due to nuclear fallout, and then to the parts of atoms and why some elements are radioactive and some are not.

I also found that I would have to assign specific blocks that prioritized group work. It’s hard, apparently, to arrange everyone’s schedules to do group work, even when you’re with the same group of people, in the same classroom, all day at school. Part of this though is that, in giving students so much control of their time, students find their own rhythms to the days, with, say, math in the mornings and language after noon, that may not match up well with each other. So I’d find myself saying, when we restarted after lunch, “Remember your group projects are due tomorrow, so you might want to get on that.” And, typically, they did, getting the group work done before going back to their individual work.

The key difference with a set time period for each class, is the tendency for the teacher to feel that they have to stay on subject for the entire period. There are, of course, different topics and subjects that need the full period or block, and I certainly favor having a longer time period to work with, but there are times when you might feel the urge to artificially stretch the work just to fill in the time. This problem was mentioned in the article:

Another complaint: boring 45-minute classes became boring two-hour classes. Robert Ronan, a senior, said, “There are some classes that lend themselves more easily to 2-hour-and-15-minute classes and teachers that can do that, but I sort of feel like a lot of the classes are the same, just stretched.”

–Anderson, 2011: At Elite School, Longer Classes to Go Deeper

It seems to me, that if you don’t want to lecture or have a discussion for entire two hours, which could get boring if not done really well, and you want individual or group work, which some students will complete faster than others, you are going to be faced with students who have time on their hands. You’d prefer that they spent that time productively, and definitely don’t want them distracting other students, so there need to be clear expectations about what they should be doing in these interstitial moments.

Sometimes you just need a nap to rest and recuperate.

I’d lean toward making sure they know how much time they have before you need their attention again (or they have to leave) and then giving them the choice of what to do: they could start on homework for this or even another class; they could take a quiet break to relax and recuperate (journaling might be a good idea); or they could do what you’re probably doing, and go around helping their peers with the work at hand.

Within the same block of time:

Within the same block of time, peer-teaching (math in this case) occurs at one end of the classroom.

The group splits and reforms around individual work, but with company close by. These students are working on the same subject, and will occasionally ask each other small questions about the work, but are working individually.
At the other end of the classroom a pair of students work on their small group project (science).
And another student works on something completely different (his research project) in a different, quieter space.

Blind Sampling of the Subsurface

Extruding sediment from the corer into the sieve. Dashed lines indicate where the piston and metal rod extend inside the barrel of the corer.

On the first morning of the Coastal Science Camp, between dip netting and seining at the estuary, we tried sampling beneath the seabed using a little coring device which I seem to have to forgotten the name of.

Some students were quite excited about the chance to sample beneath the surface of the sediment. Student displays the sampling device is in his right hand.

Usually, they can see the little holes in the seabed where the benthic macrofauna live, but not this time. All the sediment pouring into the Mississippi Sound from this spring’s swollen rivers had made the waters too turbid to see through. So we were coring blind.

The corer is simply a metal (stainless steel) barrel with a rubber piston inside. The piston is connected to a handle at the top with metal rod. To sample, you put the tip of the barrel at the sediment-water interface and push the barrel into the sediment at the same time holding the handle steady to keep the piston from moving into the sediment. Holding the piston steady provides a little suction on the inside of the barrel, which helps the barrel move into the sediment, and keeps the sediment in the barrel when you pull it out. However, it does help to put your hand on the bottom of the barrel as soon as possible to keep the sediment from falling out, even if that means sticking your hand into the sediment itself.

Keeping you hand on the bottom of the barrel keeps the sediment from falling out before it gets to the sieve.
Vague layering is visible in the sediment.

Once you’ve recovered the sediment, you extrude it into a sieve. Sometimes you can see a little layering in the extruding sediment, but we did not take the time to try to interpret it since our focus was on finding benthic fauna.

The sieve’s mesh is pretty coarse, so anything sand sized or smaller is washed out as you gently rock it back and forth in the water. We did not find much. Mostly small pebbles. Without being able to see the seabed our sampling pattern was pretty random.

Small pebbles in the sieve.

The more persistent groups (the class had been broken into groups of two or three) did find a couple things, including a polychaete, which is a segmented worm.

A polychaete.

They also turned up a small, clawed, lobster-like organism:

We also found the burrow of an unknown organism, surrounded by a clayey cast. It looked very much like some of the fossilized burrow casts we saw at Coon Creek.

Burrow, with surrounding cast.

This type of sampling was not everyone’s cup of tea, however. Fortunately, the water was shallow and warm, so a good time was had by all.

Some groups were less successful at finding benthic macrofauna than others. They had other things on their mind.

Building the Machine: The Role of the Teacher in a Montessori Middle School

With students working on different things at the same time, sometimes collaborating, sometimes working individually, a fluidly function Montessori classroom is somewhat akin to a complex but well-oiled machine: there are lots of individually moving parts that sometimes interact and sometimes not, in an ever-changing configuration. As a result, the job of the middle school teacher is less to convey information than it is to develop a successful classroom culture and ensure its efficient working.

Building the machine starts with the teacher as a role model. The teacher is a role model at all levels, but in middle school this takes on a slightly different color. After all, your adolescents are furiously figuring out how to be adults, so they’re taking a lot of clues for their behavior from the adults in their presence. The key things they’re looking for are, in Montessori’s (1948) words, “a sense of justice and a sense of personal dignity.” The trick is that underneath all the cynicism, they’re all idealists.

Justice is a particularly important and delicate concept because students want justice badly, but they tend to see it as distributive justice, where everyone is equal and get equal rewards and punishments. Unfortunately, this view tends to lead to an over-expansive expectation of rights and often to a sense of entitlement: the belief that if that person is getting something, I should get the same thing too. What’s too often missing, is the recognition that beyond the basic human rights, rights and privileges have to be earned.

This is something I find that I have to explain again and again for everyone to internalize what it means. It does not help that adolescents’ frontal cortex, the part of the brain responsible for critical thinking and impulse control, are not yet fully developed. What makes things even more interesting is the fact that girls tend to cognitively mature a lot faster than boys.

In addition, my own philosophy is that there are two key things I want to impart to my students: a love of learning and the willingness to try new things. This is somewhat contrary to where students are going developmentally. Adolescents tend to chase certainty as they change physically and mentally, all the while trying to establish their personal identities and place in the world; their focus tends to narrow toward what they’re good at and where their interests lie; there is “an unexpected decrease in intellectual capacity” (Montessori, 1948).

To encourage independence and creativity, and to build the sense of personal dignity through accomplishment, I sometimes break the pattern of the Montessori three-part Lesson (introduction, practice, application), and throw them assignments that they should have most of the background tools and knowledge to deal with, but have never encountered in this particular way. The Student Run Business is great for this, as unexpected problems are always cropping up, and, in case of emergency, it’s easy to create extra problems and challenges if you need to. When our bread-baking ovens started acting up, the oven calibration provided a great opportunity. It needed to be done, and students could figure it out on their own. Mostly. Eventually.

Developing a good classroom culture is probably the hardest challenge for those new to Montessori, especially with early adolescents who tend to have their own ideas and know everything already. However, with a few carefully designed lessons and exercises, the machine takes care of most of the teaching and learning of math and science and social studies and whatever else the curriculum requires students learn, peer-teaching and collaborative learning are all part of the classroom culture. The best part though, is that, once well established, the teacher ends up with a lot less work to do, and with a culture that propagates itself from year to year in our multi-aged classrooms.

So while we want to create a well organized, fluidly functioning classroom, it’s sometimes useful to introduce a little extra friction to keep things interesting. Of course, most often you don’t have to do this yourself. A lot of friction will come from the students themselves, and then the trick is anticipating it, allowing students the chance to deal with it, and then finally using it as a lesson so students learn from their experience if it gets beyond them. All the while, you must recognize that your every word and action is being carefully scrutinized with an eye for justice, even though you and they may not have the same definition for the word.

References

Grazzini, C., 1996. The Four Planes of Development, The NAMTA Journal, 21 (2), 208-241.

Montessori, M., 2005. From Childhood to Adolescence, The Montessori Educational Research Center, Trans. New York: Schocken. (Originally published in 1948).