As a new middle-school teacher, I’m facing a challenge I never thought about before: assigning a list of school supplies for my students. My colleagues tell me that there’s a real downside to wooden pencils, since it gives students an excuse to get up every few minutes and use the pencil sharpener. But am I being environmentally irresponsible by asking parents to buy plastic mechanical pencils?
The Lantern is sympathetic: It’s hard enough evaluating the relative ecological impact of two products without having to also worry about the social lives of sixth-graders. But being a one-time sixth-grade boy himself, the Lantern is pretty sure that your students will find some excuse to get up from their desks anyway, so he’ll stick to the environmental question at hand.
Since both mechanical pencils and the regular kind contain similar “lead” (a combination of graphite and clay), the primary decision here comes down to whether you’d prefer your kids buy plastic or wood. As far as the Lantern can tell, most low-cost mechanical pencils are made of polystyrene or one of its relatives. Like other plastics, there are two major downsides to polystyrene: First, it takes quite a bit of petroleum to make, and second, it’s not easy to get rid of after you’re done with it. The best data available suggest that manufacturing 10 grams of polystyrene—a rough estimate for the plastic you might find in a standard mechanical pencil—would require about 22 grams of oil, between the petroleum that makes up the plastic and the energy needed to manufacture it. And the process of creating plastic is going to produce its own chemical waste. While the mechanical pencil has the advantage of being reusable—more on that in a moment—it’s almost certainly going to end up in a landfill at the end of its life.