Tuesday, June 07, 2005

Wacky class story.

In the education biz, we call it constructivism. The idea is that I don't tell kids answers...I guide them to figure it out themselves. This means, from time to time, that I don't jump in and say "Hey, that's a silly idea," and it takes us to some bizarre places. Like the following place:

Kids are working on a fairly tough assignment. They are to research a disease in an assigned region of the world, develop a solution to their epidemic, and then give a presentation to the World Health Organization asking for money to bankroll their solution. Recently, my lil' cherubs were in the library working very hard and earnestly on this assignment when I had the following exchange. The kid was working on a mosquito-borne disease in South America.

ME: Okay. What's your plan?
STUDENT: We've decided to spray all of Brazil for mosquitoes.
ME: All of it? Or just some parts?
STUDENT: All of it. We're playing it safe. But we need to know how much pesticide to spray.

[At this point, I am stifling the points about environmental impacts and health side effects that the Brazilians might not care for. She'll get there herself. I know she will. I KNOW she will.]

ME: How are you going to figure out how much pesticide you need?
STUDENT: I've found this website.

[On the screen: a pesticide company website. You put in how much area you want to cover, and it tells you how much pesticide you need...and the cost.]

ME: [still stifling my anti-constructivist urges] Okay.
STUDENT: But we have a problem.
ME: What's that?
STUDENT: We don't know how many square feet Brazil is. This needs to know how many square feet we're spraying, and we only know the square miles. It's 3,286,470 square miles.
ME: [exploding in an effort to maintain constructivism] Okay. How can we figure that out?
STUDENT: Multiply by 5280.
ME: Okay. Get the calculator. How many square feet in Brazil? [I briefly mull over how I never thought my career would lead me to ask that question]
STUDENT: [points to calculator, which now reads 17352561600]
ME: Right. 17 billion, three hundred fifty-two million, five hundred sixty one thousand, six hundred square feet.
STUDENT: Okay.
ME: [waits a time for constructivism to work]
STUDENT: [silence]
ME: [stops waiting] All right. Put it in the website...let's see how much pesticide you need.
STUDENT: Okay...[enters the number, reads the result]...It says we need infinity gallons of pesticide.
ME: Okay. Infinity gallons. What does that tell you?

[ME and STUDENT stare at each other. It's a standoff. Enter STUDENT'S PARTNER.]

STUDENT'S PARTNER: Wait! That's not right.
ME: Yes. Why isn't it right?
STUDENT'S PARTNER: We need to spray Peru, too!




Update: My bride-to-be has pointed out that I can't get the correct number of square feet from square miles by multiplying by 5280. Unless I'm mistaken, I'd have to multiply by 5280 TWICE. So, if you're curious, Brazil is 91,621,525,248,000 square feet. Ninety-two trillion, six hundred twenty-one billion, five hundred twenty-five million, two hundred forty-eight thousand square feet. So MUCH more than infinity gallons of pesticide.

Anyone want to add Peru to that?

3 comments:

Murky Thoughts said...

If you're trying to get your mist on the ground and it's just as likely to stick to foliage, then the area that matters includes the leaves and stems and trunks down to undulations of the droplet size. If you're spraying atoms on a beach you need to know the distribution and the size of the sand grains. For herbicide you might do well to know the distribution and species of plants. I can't help thinking it would take a different amount of paint to coat an acre of wheat than an acre of bannas...although universal constants pervade the natural world, so who knows? Hmmm. Maybe my geekiness is interfering with a proper appreciation of this story...

tommyspoon said...

My only thought is that I don't want those students in charge of fumigating my house...

lemming said...

(laughs long and hard)

I hate to mention this, but I think the Panama Canal builders finally overcame their malaria problem with soem heavy duty spraying. Mind you, I'm not sure, and it was a rather smaller area...