SAN LORENZO -- Sometimes building young minds means letting young minds build.

So it goes in the Sustainable Earth Systems class at KIPP King Collegiate High School, a public charter school. Juniors and seniors are thinking up and executing their own earth-saving projects under the supervision of James Bording, a former engineer who has been teaching for three years.

"It's been a cool process, and I've changed the way that I think about teaching," Bording said. "In this class, I'm more likely to ask a student what they need from me rather than them ask me what they should be doing. The class is entirely student-driven, they're allowed to explore and think and design ... and they have stepped up and done some incredible things."

Some students built and tend to an aquaponics tank, in which small water animals live symbiotically with plants being cultivated. Some are building a biochar furnace that produces a kind of charcoal which both enriches soil and holds carbon dioxide in that soil, preventing it from being released into the atmosphere.

And some who built and tend an outdoor garden -- featuring cantaloupes, fava beans, fruit trees and more -- found that one sustainability measure often leads to another. While "double-digging" a garden bed to boost soil drainage and aeration, they hit a vein of clay. Students decided to use that clay to build a "cob oven," so they can turn some of their garden's produce into pizzas and teach the rest of the school that there's more to nutrition than snack chips and sodas.

"This is our third oven, the others have fallen apart," Bording admits. "But the kids aren't discouraged, they just say, 'OK, we learned, and we'll try again.'"

Everyone has a part to play, no matter their interests and skills. Bording said one student early on was "spacing out" while staring at ladybugs in the garden; with some discussion and encouragement, that student is now the class' entomology and organic pest-control expert.

McKenna Brown, 17, said the class is special "because I am able to pick what I want to focus on and how that project will develop." She's writing grant proposals for the class so other groups can build their projects, she said. "Writing is what I love doing, so it's really cool that I am able to do that for the benefit of our entire class."

Bording loves the energy -- sustainable energy, one might say -- that his students are bringing to their work. "It's cool to have this space where students are allowed to just try, and there's no motivation other than their own desire to try to figure it out and learn it."