They might not yet understand words like "bioswale" and "photovoltaic."

But the 300 kindergarten and first-grade students who start next month at Punahou School’s new, $26 million, 2.5-acre Omidyar K-1 Neighborhood complex will understand what those words in action mean—when they see rain caught in the bioswale irrigating native-plant gardens or when they calculate how much energy photovoltaic panels on their classroom rooftops generate.

"We want them (to know) they indeed are a part of the ecosystem," said Mike Walker, Punahou junior school principal. "It’s essentially a whole new system of learning."

The school complex is poised to be named the largest building in the islands with platinum certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design, or LEED, standards.

If the certification is approved, the complex also will be the second-largest school building in the nation at the platinum level.

Among the environmentally friendly components in the seven-building "neighborhood": the bioswale, or water catchment system; photovoltaic panels that will generate about 60 percent of the complex’s total energy demands; the use of skylights and natural ventilation; and classroom countertops made from recycled wastepaper.

Construction on the 2.5-acre complex started in February 2009 and wrapped up last month.

During a walk-through with reporters yesterday, Walker said that before kicking off the K-1 project, Punahou already had decided to incorporate two elements into its design: environmentally friendly building innovations and cutting-edge early childhood brain research, both of which also went into the curriculum for students.

For an example of how brain research went into design, Walker said, look to the playground, where in addition to the traditional slides and hanging bars, there are large rocks. Why? Research has found that climbing stimulates brain development in young children.

The playground also has walking bridges over a tiny dry-bed stream that children will be encouraged to explore.

"At the end of the day, we want dirt underneath their fingernails," Walker joked, adding that he wants to see the complex become a model for early childhood learning at public and private schools in Hawaii. "This is innovative. We do think this can be a resource for our community."

Punahou has 150 kindergarten and 150 first-grade students.

The complex is named after eBay founder Pierre Omidyar and his wife, Pam, who kicked off a capital campaign for the new complex with a $6 million challenge grant.