I bring this up because I nearly brought it up back in February when my Vice Pule asked if I’d feel comfortable teaching a science class. As part of my credentials, I nearly submitted my RadioLab podcast subscription, but then I thought the better of it.
On one hand, I feel completely qualified to teach my year 9 science class. Though I didn’t major in science, I did well in the science courses I took in college. In fact, I’ve always done reasonably well in science going back through high school and middle school. And my cursory interest in pop science keeps things fresh. RadioLab is just another installment in a long line that’s included Mr. Wizard, 3-2-1 Contact, MythBusters, and Discover Magazine.
On the other hand, I feel like I could be exposed as a phony any second.
I felt like I came stunningly close today when the text book gave me a question to pose to the class, but didn’t supply an answer, as though it was obvious I should know. The bizarre thing was I had pondered the exact same question less than a week ago.
As I mentioned in Odds and Ends last Thursday, I walked my bike to the Peace Corps office to get fill up the tires. While working the pump, I got to thinking, just why do we fill rubber tires with air? Why not a cushion of pressurized water? Or, for that matter, why do we need cushioned tires at all? Why not ride around on tires of solid rubber? Looking back now, the answers to these questions seem obvious, but at the time I didn’t come to any definite answers.
Fast forward to today when after the lesson about solids, liquids, and gases—we got farther than I had planned—the book asks, “Why do we fill car and bicycle tyres with gas?”
I find moments like this are when my teaching is at its best. It’s happened before when a student asks a good question and I’m immediately forced to re-think the material, wracking my brain for reasoning, pulling a rabbit out of a hat I hadn’t intended to wear. Students recognize when I get into territory I hadn’t intended to tread, and I actually think it brings an air of spontaneity and freshness to a lesson.
I was greeted with silence when I posed the question, and then one kid raised his hand. “It’s easier to recycle air. It’s all around us, and it can be used and reused easily.” Not the answer I was looking for, but shockingly astute. That kid gets an A.
What was the answer I was looking for? I thumbed through today’s lesson again. Of course. Gases are far easier to compress than water. And gases expand to fill a confined space, ensuring constant pressure throughout the entire tire. A tire filled with water would be heavy and, even if you could pressurize the water, if pressure decreased at all, a bike ride would be sloshy and uneven. As I said, this seems quite obvious now, but last Thursday bike tires filled with water seemed whimsical.
And science is always most fun with a little whimsy. For proof, tune into RadioLab.
I hope you’re well. Pictures below.
We're doing impromptu speeches in my year 10 English class tomorrow. This is a list of possible topics.
There's a guy working in the alcove on the right. If you look closely, you can see there's no floor. Also, he's 3 stories off the ground.
"Curry Pockets" from K.K. Mart, the store next to the Peace Corps office, are a favorite among volunteers. Until today, I'd never had one. They lived up to the hype. They were delicious.