Monday, July 2, 2012

Good and Bad Science Instruction

My sixth-grade teacher – we’ll call her Mrs. Brandenburg – decided that my class needed some creative instruction in the grade-school curriculum’s stepchild: science. To pursue her lofty goal, she gave us three science lessons over the course of 180 days of instruction. That’s one whole lesson every three months. Or to put this impressive record in another perspective, we got three more lessons than Einstein got in the year after he dropped out of school.

The first lesson covered the noble science of geology. Mrs. Brandenburg bought one set of rocks for the class to examine. She labeled them and then asked us to fill out a chart in which we reported the sensible characteristics of each rock. In the most useful part of the lesson, we learned that one rock is harder than another if it can scratch the other. In the most memorable part of the lesson, though, we learned how the rocks tasted. One by one, each of the thirty students walked up to the table and licked each of the ten rocks. I remember my experience clearly: “Licking rock no. 1 now. Hmmm. Tastes like a rock. No. 2? Tastes like a rock. No. 3? Yep, like a rock. No. 4? Rock again. No. 5? Oh! Tastes like salt. No. 6? Oh well, back to rock taste.” And it was rocks from then on. The saliva and germs of the other students had no discernible taste.

The second lesson revealed to us the wonders of the Doppler Effect. Mrs. Brandenburg first had us draw graphs of the sounds of cars. I don’t know what kind of graphs others turned in. I know my chart showed three dramatic rises separated by sudden drops, the sound the sixth-grade boy expects to hear every time he gets behind a wheel when eventually given the chance. Mrs. Brandenburg, curiously dissatisfied with our pictures (well, all but mine), told us she needed to try something different. So she took us out to the hall and held up two pieces of construction paper: one light green and one dark green. “Which one is lighter?” she asked. “The one in your right hand,” one student answered with a confused giggle. Then she walked down to the other end of the hall, held up the two sheets of paper, and asked with a knowing nod and a clever lift of one eyebrow, “NOW, which one is lighter?” “The one in your right hand,” I responded tentatively. Mrs. Brandenburg immediately looked puzzled, took a quick look at each piece, and walked back toward us with disappointment on her face. The speed of her return walk was no closer to the speed of light than her departure had been.

For the third lesson, Mrs. Brandenburg began by telling us she hated grasshoppers. “As a result,” she announced logically, “I want you to count the grasshoppers in the schoolyard.” Our method began one Friday afternoon with the stretching of twine across the playground, east-to-west and north-to-south, to lay out a grid of one-yard squares. She assigned each of us to one square and told us to count the grasshoppers there. Now a lesser teacher might have thought to extrapolate from the count of those first thirty square yards and estimate the count in the whole area by multiplying by the ratio of student squares to the entire square yardage. But that method would have yielded only an approximation, and Mrs. Brandenburg, scientific thinker that she was, wanted an exact result. So, announcing that we would finish the project on Monday, she gathered up all the string and handed me the wad, giving me the weekend assignment of untangling it. Sometime around Saturday afternoon, my parents’ objections to my obsessive (but unproductive) work with the string grew so strong that they ordered me to stop doing my homework. On Monday morning I quietly dropped the ball of string on Mrs. Brandenburg’s desk, and she just as quietly dropped the grasshopper census.

Thinking of Mrs. Brandenburg naturally leads me to thinking about Mortimer Adler, the moving force behind the Britannica Great Books set. In his helpful guide called “How to Read a Book,” Adler explains that the books by the seminal thinkers are generally within the grasp of the average reader: these books usually aren’t written for experts since, in the case of a book that reports a new idea or science, no experts other than the author exist. Way back in the fist year of my first ten-year plan, I found Antoine Lavoisier’s Elements of Chemistry the perfect example of Adler’s pattern. Lavoisier didn’t write to other chemists; since he discovered and named the first element of the modern table, there were no other chemists to write to.

Lavoisier carefully explains all his experiments in simple terms, showing how he divided common substances into parts and combined the parts again. Measuring the mass of the total and of the parts, he showed that one truly came from the other. This astonishing genius started from scratch. He didn’t order his two-necked beakers from the science-supply store; he had to design them himself and ask a glassblower to create them. His wife then drew illustrations of all the equipment so readers could see the fantastic vessels for themselves. He didn’t start out trying to prove that water was made of hydrogen and oxygen; his predecessors said that water was an indivisible, elemental substance. But he found that the “one” element was actually made up of two. Lavoisier also divided the previously indivisible air into two constituents: one breathable and one unbreathable. Since he discovered these two elements, he earned the right to name them. He decided on oxygen (“acid-former”) for the first of the two fundamental gases, since it also makes acids when it comes into contact with certain metals. The other he called azotic gas (“contrary to life”), considering the name nitrogen, but eventually rejecting it as not accurate enough. Well, he got his way half the time.

The story of Mrs. Brandenburg is completely true, by the way. I’ve only changed it in the one way that Jack Webb would approve of. I thought of her one day soon after sixth grade while I was waiting at a railroad crossing and heard the engine’s horn as it raced past. I also thought of her many years later when I read the story of Alexander the Great and the Gordian knot.

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