It's one of the reasons the 31-year-old scientist-turned-teacher was recognized today as one of 61 top public high school teachers in the Philadelphia School District.

So when Yousuf Khaled, a 10th grader in VanKouwenberg's advanced engineering class at the Science Leadership Academy in center city Philadelphia, said one recent school day that he'd like to bake a "pie-sized" cookie, VanKouwenberg chatted him up. He'd have to bake it for a longer period of time at a lower temperature to avoid burning it, while fully cooking it, VanKouwenberg told him.

"What is it that controls how long it takes for the heat to get to the inside?" asked VanKouwenberg, affectionately called V.K. by students.

"Oh, bigger surface area," Khaled shot back.

"There you go!" VanKouwenberg said.

"Finally, my geometry has an application," sighed a smiling Khaled.

VanKouwenberg for the last several months had used the analogy of sending cookies through an oven on a conveyor belt to teach students the science behind building a biodiesel reactor that would continuously process fuel. Biodiesel typically is made in a "batch" process, rather than the more efficient "flow" process designed by his students.

VanKouwenberg and his students are seeking a patent for their reactor, built with sheet metal and PVC pipe from Home Depot, a window box, leftover fabric from a science fair and a screen that fell out of a window at the school, at 22d and Arch Streets.

And, the device soon will be replicated by a remote community in Ecuador - a connection brought about by an employee at the academy - and used to increase fuel capacity for a local school and geotourism lodge there.

Such is the real-world learning, 21st century style, that plays out every day in VanKouwenberg's classroom, dubbed the "VanKave" by students who have been so awed by their teacher's seeming omniscience that they started a web chat about it.

"Even if his topics are so boring that you really don't want to pay attention, he makes you want to learn," ninth grader Stephen Farrington, 15, said in an interview. " I mean he sells everything, and he sells it like a Mercedes Benz dealer....Frankly, I think it's rubbing off."

A new recognition

Since 1961, the foundation, funded by the largesse of the late Christian R. and Mary F. Lindback, who made their fortune running a Philadelphia dairy company, has given $4,000 teaching awards to professors at more than 50 area colleges. In recent months, foundation trustees decided to recognize high school teachers who motivate and inspire their students in what has become perhaps the state's most embattled school district.

"You don't get enough recognition, and what you do is so essential. The future of Philadelphia really rests on your shoulders," Sheldon M. Bonovitz, a foundation trustee told winners at the ceremony. "If we don't really have an educated school force, we're not going to have a vibrant city."

Bonovitz said trustees hope other organizations are inspired to make similar contributions. This year, the foundation, whose mission is to further education, donated more than $213,000 in prize money to school district teachers in what officials say will be an annual recognition.

The effort has drawn praise in and out of the district, including an endorsement from Gov. Rendell.

The winners

They share a willingness to work beyond the school day, a knack for cooperating with colleagues, strong knowledge in their subject and an ability to connect with students.

"She's still the teacher that you'd rather die than disappoint," observed Saha Ovetsky Fradkin, a Central High School graduate who penned a nomination for her history teacher Pat Hansbury.

While there is no universal definition of a "great teacher," experts generally agree that the best in the profession are experts in their subjects and use a range of methods to teach it. They adapt to individual student needs and are always learning themselves. And they move student achievement forward.

"It sort of boils down to knowledge, skills and disposition," said Joseph Aguerrebere, president of the National Board for Professional Teaching Standards.

Stephanie Corbin, a 36-year veteran at Dobbins Vocational Technical High School, has proven herself a master at teaching students to write, yielding praise from colleges that have noted the strength of her graduates. Her students have coined the lessons "Corbin's words."

She has made a second job of collecting material from college fairs to help her students make the right choice.

Corbin said she begins each school year the same way.

"I try to find something I like about each child, even if it's only a dimple," she said.

At Bodine High School for International Affairs, it's hard to find an activity in which English teacher Gina Hart isn't involved. Hart, who has taught there since 2002, runs the poetry club, the Latino writers forum and the mentally gifted program. She sponsors the Asian club, the theater program and the yearbook and coaches the academic club.

On the Martin Luther King Jr. holiday, she drove students to her alma mater, Swarthmore College, for a tour.

Legna G. Melendez, who teaches English as a Second Language at Edison High School, has taken into her home students in crisis, purchased eyeglasses for them and paid for their prom and graduation tickets. At the same time, students in her Advanced Placement Spanish class have excelled on standardized tests.

Some winners inspired students with their character.

"Your most important feature is the outstanding urge you have to do what's right whether it be plant organic vegetables, or offer people free soil tests," student Harold Pearson-Nadal wrote of Jessica Naugle, a teacher at Saul High School for Agridultural Sciences.

For some, the connection was powerful and personal.

A former student of biology teacher Donald C. Snyder Jr. wrote that he was the one teacher who stopped him from dropping out a month shy of graduation at South Philadelphia High School.

The all-knowing V.K.

"Knowledge is power, and that is why the VK is the all powerful," one student wrote on a web chat.

"There should be a VanK monument," penned another.

"Is there anything that can be erected to show the VK's total awesomeness?" chimed in a third.

Students apparently settled for a sign on his door: "Welcome to the VanKave!!! (His awesomeness)"

One recent afternoon in his classroom, stocked with plants and half-filled glass beakers of science experiments in progress, he stunned his young charges again when a biochemistry lesson led to a student-spurred discussion on whether drinking urine would help a dehydrated person.

It would not, VanKouwenberg assured.

"You'd have to drink four glasses of water for every glass of urine you drink to get back to the same level of hydration," VanKouwenberg told the class, between swigs from a coke bottle and cold medicine - his remedy for beating a nasty cold and 103 fever while teaching.

How did he know that?

"I don't know. I read a lot," he said.

Since fifth-grade, Vankouwenberg wanted to be a teacher. Growing up in Lancaster, the son of a minister and a math teacher, he said he had many good teachers who motivated him and furthered his logic. His chemistry teacher had been a chemist at Dupont, giving him the idea of a career in the sciences before teaching.

After getting a bachelor of science in chemical engineering and biomolecular engineering at the University of Pennsylvania, he became a pharmaceutical researcher. Unfulfilled by the work, he quickly switched to teaching. His first job was at West Philadelphia High School.

After nearly five years, he opted to be a founding staff member of Science Leadership Academy, which opened in fall 2006 and currently serves grades nine and 10.

"Here, I get to try different things," said VanKouwenberg, a bachelor who lives in West Philadelphia.

He wrote the school's engineering curriculum and co-wrote the biochemistry curriculum. He's also the engineering club adviser and cross country and track coach.

"The wonderful thing about VK, much like all the teachers in the school, they truly love their subjects and they're incredibly passionate about their subjects," Science Leadership Academy Principal Chris Lehmann said. "But they love teaching and they love kids more. That's the sweet spot you want to live at."

It took VanKouwenberg's students 30 to 40 tries to figure out the biodiesel reactor that uses lye, methanol and oil. The final device, which is five feet by three feet by three feet, soon will be welded at the Franklin Institute.

"We're not just learning something to learn it," said sophomore Alison Campbell, 16, donning a white lab coat - the uniform of the small magnet high school. "It's letting us see what we're learning in class can actually do."

Gushed classmate Sam Beccaria, 16: "It's awe-inspiring."

The school is working on the patent application with the pro-bono help of lawyers from GlaxoSmithKline and the Franklin Institute.

The Yachana Foundation in Ecuador hopes to replicate the reactor in the next year. The complex includes a school, a non-profit foundation and a chocolate company and is in a small village on the Napo River in the Amazon region, hours away from fuel sources and only accessible by motorized canoe. Trucking in fuel is expensive, and there are times when the complex runs out, said Douglas McMeekin, the foundation's executive director.

He was thrilled with the invention from VanKouwenberg's students.

"I like their willingness to work with an organization like ours that is in need of this kind of thing and that is in a location that has nothing," McMeekin said.

Meanwhile, VanKouwenberg is planning other patent-worthy lessons. He envisions wind turbines and solar cells. Eventually, he hopes the science academy can be fully powered with alternative energy sources. It will take zoning variances and money.

Principal Lehmann admires VanKouwenberg's aspiration: "Even if we fall short, what a wonderful goal."