Tuesday, November 24, 2009
Musing in retirement
I'm often asked if I miss teaching, which after more than forty years in the classroom is a reasonable question. The answer, generally, is no. Now that the pension checks appear in the bank each month, I'm happy to spend my time learning rather than teaching. The next question, I suppose, is why learning? Why bother stuffing more stuff into the head when...when it's all going to evaporate soon? Well, because I can't think of anything I'd rather be doing.
But back to teaching: Do I miss it? Only occasionally. Like yesterday morning when the image above was the APOD (Astronomy Picture of the Day): a view of Earth from the third flyby of the European Rosetta spacecraft on its ten-year journey to a rendezvous with Comet Churyumov-Gerasimenko in 2014.
A breathtaking picture. And, as they say, a teachable moment.
I'd love to project this image onto a huge screen in a darkened classroom, and then spend an hour talking about it. Not lecturing. Just asking questions.
For example, the APOD text says we are looking at "a bright crescent phase [of the Earth] featuring the South Pole to the passing rocket ship." Presumably they mean the white mass at the bottom center of the crescent is Antarctica. Can that be right?
Time to get out the 16-inch globe. Where is the Sun? A spotlight will serve. Now let's reproduce the crescent. The flyby was in mid-November; what was the orientation of the Earth relative to the Sun? Can we find the image's time of day on the ESA (European Space Agency) website? Let's sort out exactly what we are looking at.
Here's a closer look at the crescent (click to enlarge the pics). Notice the illuminated cloud tops in the shadow at bottom right. How high are they? Can we work it out? Sure. All we need to know is the diameter of the Earth. A few measurements off the screen and a big sketch on the blackboard will do the trick. This is how Galileo estimated the height of mountains on the Moon.
Some years ago, Eric Hirsch published a A First Dictionary of Cultural Literacy: What Our Children Need to Know, a compendium of core knowledge that he believes kids should acquire by the time they enter junior high school. The chapters on science list 442 terms, from acid to x-ray. It's a good list, but, as Hirsch would surely be the first to acknowledge, a vocabulary is not a sufficient basis for scientific literacy. What is required is a gut feeling for how the world works and our place in it. And a sense of wonder.
That's what I miss about teaching. Give me an image of the crescent Earth looming -- breathtakingly -- in a darkened classroom and I'll do my very best to send a student's imagination hurtling through space into a universe that is deep and vast beyond our present knowing. Once you've caught the virus of wanting to know, the 442 vocabulary terms will come along in their own good time.