Chris Jenson certainly looks like nothing but a high school science teacher — and a good one — as he unleashes his chemistry students to the day’s laboratory experiments.

They are ready to explore the physics of gas and liquids, crushing aluminum cans without touching them, sniffing the dissipation of acrid smells.

Then you hear it.

“Doc Jen!”

A girl in goggles has called out, hand waving, needing her teacher’s assistance.

“Doc Jen!” comes another student’s call.

Or, other times, they simply say:

“Doc!”

You see, the students here in Blue Valley Southwest High School know the back story. They know he is Dr. Jenson.

And they’re not talking of an academic with a Ph.D., but a medical doctor.

A practicing physician.

He’s good at that, too.

It’s striking, his students agree, that he is here every school day ready and eager to teach, having relegated medicine to his moonlighting job.

Senior Christina Granzow, 17, like her lab mates, knows something about the prestige of doctoring, the financial rewards and, even more so, the infamously difficult journey of medical school and all those years of residency.

But here he is, in their classroom.

“He must really love to teach,” she says.

He makes it look easy now — if teaching a high school science class can ever really look easy for anyone.

Jenson, 35, in his second year as a high school teacher, recently won one of Kansas’ Horizon Awards honoring stellar first-year teachers — showing him that, yes, he did the right thing when he went back to school yet again four years ago to learn how to teach.

That doesn’t mean the idea didn’t sometimes terrify him.

He talked it through over and over with his wife, Robin, 34, who is an anesthesiologist.

Teaching is hard. And it requires a skill set that is in no way guaranteed just because someone was good at medical school.

And then there were those first reactions every time he verbalized his I-think-I want-to-be-a-high-school-teacher idea.

There was Lynn Martens, a Blue Valley teacher whom Jenson contacted early on for advice via a mutual connection.

“I asked him, ‘Are you sure?’” Martens said.

His adviser, Jim Ellis, an associate professor of curriculum and teaching at the University of Kansas, also was seemingly taken aback, Jenson recalled.

** Why do you want to do this?

Both Martens and Ellis are quick to add that they were soon won over by Jenson’s enthusiasm and his deeply considered commitment to his plan.

But it was unusual.

Ellis, in overseeing KU’s graduate licensure program, has shepherded many career-changers from science and math fields into teaching degrees.

Most often they are people new in their fields who decided early on that they saw themselves more as teachers rather than “a Ph.D. doing research,” Ellis said.

Over the years he has seen some lawyers, some engineers and even a dentist among those changing careers to teaching.

But in his 16 years with the program, Ellis said, Jenson was the first and only medical doctor to come calling.

Let’s take this back a bit.

It’s 20 years ago. Rebecca Merrill’s ninth-grade biology class in O’Fallon Township High School in the St. Louis area on the Illinois side.

The teenaged Jenson — Chris — is a bit extra exuberant this day. Asking a lot of questions.

Maybe too many questions.

At one point the teacher tells Chris she wants him to stay after class.

“I thought I was in trouble,” Jenson recalled.

But the teacher has a question for him, or more of an observation.

She wanted to know if he had started shaping his post-high school aspirations yet.

“I hope it has something to do with science,” he remembers her saying. “Because you’re good at it.”

Education had always been important in his upbringing. His mother was an elementary and preschool teacher. His father was a U.S. Marine, whose career moved his family around the country until they settled for a while near St. Louis.

But hearing that declaration from Ms. Merrill was a bit of a jolt.

She was a no-nonsense teacher. Demanding. High expectations.

He later took advanced placement biology with Merrill and was, by the end of the course, convinced he was bound for medical school.

First came undergraduate studies at the University of Notre Dame in Indiana.

Then he was accepted into the Loyola University Chicago Stritch School of Medicine.

There he meets Life-Changing Teacher No. 2: Dr. Kevin Simpson.

Simpson’s medical specialties were internal medicine, critical care and pulmonary disease.

But he was even more a master in prodding and inspiring the medical students who came under his care.

Jenson got to work with him twice.

He was forever calm under the stress of emergency care.

Always smiling.

Kind, but a relentless perfectionist. A hard teacher.

Even when the medical team’s response to a patient’s crisis seemed button-down perfect, he found teaching moments.

“You’d think, ‘That was by-the-book. That’s as good as it gets,’ and he would say, ‘This is what we could have done better,’ ” Jenson said.

He had an easy rapport, helping exhausted residents endure grueling 12-hour shifts.

It struck Jenson that Dr. Simpson “was always happy.”

How did he do it? Jenson asked him.

“He said, ‘The people in life who are happiest are those who pursue their happiness.’ ”

Ten-month-old Taylor Jenson is expanding her domain in the Jenson Overland Park home.

She’s raising herself up, balancing on her feet with her hands holding to furniture, motoring from coffee table to chair to couch.

Tossing toys. Ripping away the flaps of her peek-a-boo books.

As it often goes with babies and their influence, this tale is as much hers now as anyone else’s.

Just the idea of her — an imagined family — had a lot to do with the wandering thoughts of then-emergency room physician Chris Jenson some four years ago.

He and Robin had met through a Notre Dame alumni connection in 2006. He was in his third year of residency at Northwestern Memorial Hospital in Chicago. She was a third-year medical student at the University of Kansas School of Medicine.

Within four years they were married and soon were coming aware of how little they were seeing each other.

Robin, as a pediatric anesthesiologist at Children’s Mercy Hospital, had the more predictable schedule, starting around 6:30 a.m. and leaving late afternoon, depending on how long the day’s last surgery lasted.

Chris, however, was working the 8- to 12-hour shifts in the emergency room at Lawrence Memorial Hospital.

“Sometimes, we could go two days without seeing each other,” he said.

They know other physician couples that manage similar schedules and who make it work just fine, they said.

But they began to think that it wasn’t for them.

Chris’s early idea was to slide out of emergency rooms and into urgent care clinics, where the hours are more routine.

But as he thought it out, he saw an aching hole opening if he went that direction.

Emergency room doctors are constantly training new doctors.

Medical students, residents — they parade through earnestly learning, and Jenson loved teaching those doctors in training.

He did not want to give up medicine.

It also came clear to him that he wanted to keep teaching.

He and Robin brainstormed some more. She was willing to support just about anything he might come up with.

Along the way, he turned back to his mentors.

Could he teach teenagers the way Rebecca Merrill does? Could he spark their minds the way she did his?

He began seeing himself in that role, relishing opportunities to lift the confidence in high schoolers — “a chance to let someone know you’re really good at something.”

The voice of Dr. Simpson kept returning to him as well.

Wouldn’t this be pursuing his happiness?

He told Robin, “If I could go back and get a certificate to teach high school and still do urgent care, I think I’d be really, really happy.”

It was a breath-catching idea.

“But I was really, really scared,” he added.

“I hope this works.”

Which KU education student was the doctor? Sometimes it wasn’t hard to pick him out.

He was the one dressed in scrubs.

On occasional evenings and afternoons, Jenson found himself in class with other KU education students, trying to absorb lessons in teaching strategies or classroom management with a 12-hour emergency room shift at Lawrence Memorial waiting for him on the other side.

In a way he was hedging his bet, continuing to pull shifts in the emergency room while learning the teaching trade.

That meant that the life schedule he wished to simplify had to get a whole lot harder first.

The university goes to significant lengths to try to accommodate these career changers, Ellis said.

Schools are often desperate for teachers in science, math or foreign languages. Qualifying professionals who already have degrees in those fields don’t have to take more college courses in their teaching content areas, Ellis said.

They instead take a pure dose of teaching instruction and can earn their teaching certificates within 2 to 2 ½ years.

One drawback, Ellis said, is that, unlike regular students in a four-year education program, these career-changing students don’t get the same opportunities along the way to hone their skills in real classrooms.

In many cases, as with Jenson, the first and only student-teaching experience would come at the end.

He had tried multiple ways to load himself with as much insight as he could before making the leap.

He called on his high school mentor, Merrill.

She sent him her collection of lesson plans on a flash drive as part of her help.

But don’t just copy them, she admonished him. “She said that would be a disservice,” Jenson said. “I should use them to build something better.”

He visited Martens’ class in Blue Valley North High School, at her insistence.

Martens wanted to help him be sure, she said. He needed to see what teaching was about.

Though Jenson was plagued with doubt, Martens liked what she saw.

“You could tell he was somebody who saw social need,” she said. “He saw missions in life. … He wanted to embrace the rough edges and get in the trenches.”

So many people were helping him, accommodating him, encouraging him, that it added to the pressure.

He owed a debt to his mentors, the KU professors, the Blue Valley teachers and his medical team at Lawrence Memorial.

He frequently unloaded his fears on his most accommodating partner of all — Robin.

Soon the moment was quickly approaching, the February day in 2011, when he would start student teaching Dianne Dunn’s science class at Blue Valley Southwest.

Robin listened again — how he was scared he was going to let so many people down over what felt like a hunch that he would be able to teach high school students.

She was unfailingly encouraging. It all made sense to her, she said. She knew Chris would be wonderful in the classroom.

“He had this idea that some people thought was totally crazy,” she said. “But my thought always was, ‘How lucky are these students going to be?’ ”

The first case through the door, Jenson determines, is one of vasculitis.

Once he’s sure of the situation he is back in the doctors’ room at a computer, pecking out the keyboarded equivalent of a doctor’s hastily scrawled prescription.

“I can’t type,” he says, fixing the note and hitting “print.”

He’s gone in a flash. There’s a case of vertigo waiting in another room. A woman complaining of rash is checking in.

The night is just beginning at the University of Kansas Hospital’s Westwood Urgent Care clinic. Since it is all drop-ins that come, there is no telling how many there might be, so Jenson flies about his work to stay ahead, in his gray scrubs, a stethoscope slung around his neck.

He doesn’t want anyone waiting long, if he can help it.

It’s not the emergency room, but sometimes people come in with traumatic or urgent conditions — bleeding, internal injuries, dangerous fevers — and Jenson stabilizes them and sends them off by ambulance.

This Wednesday night in February ends up a bit calmer, though some of the ailments are serious and painful — a possible ectopic pregnancy, bladder infection, bronchitis and a young man who had been kicked in a nether region.

“Blunt trauma to the abdomen,” is how it was officially logged, Jenson said.

This is his routine at least every Wednesday night, sometimes on weekends, with more shifts during the summer.

It’s the part of his career shakeup Jenson knew he could do.

He comes to people who are in pain, uncomfortable or simply scared and he does what he can to comfort them.

He is still very much Dr. Jenson.

He’s also teacher.

He’s still learning, of course. Ellis notes that it takes generally three to five years for a teacher to gain comfortable footing in the classroom.

But Jenson no longer doubts his choice. The fear that dogged him when he walked into his first student-teaching assignment in Dunn’s class lasted maybe a week and a half.

By the end of the second week, he saw his lesson working. He saw students learning.

“It was the moment of truth,” he said.

He loves it now, he says, “when you see the lights go on.”

High school students are immensely capable, he says, showing off some of their work hung on his classroom walls.

One student’s work examined ventilation perfusion (V/Q) scanning in diagnosing pulmonary embolism. Another analyzed a neuromuscular blocking agent, rocuronium.

“She even wrote out the complete molecular formula,” Jenson said. “And she was right. I had to look it up.”

Jenson has relied heavily on the veteran teachers at Blue Valley Southwest to help him hone his classroom skills, and they love the enthusiasm and the real-world experience he brings.

“He gets the kids so excited,” said fellow chemistry teacher Melissa McCarty. “He is a naturally talented teacher. He’s open and very humble.”

He surprises the students. When they see they’ve been assigned to Jenson’s classroom, the students usually hear going in that he is a doctor who worked emergency rooms, and they worry what that might portend.

“I thought he might be uptight — like, strict,” 17-year-old senior Courtney Hensler said.

What they get, though, is a lively class laced with real-world stories of real patients, said 16-year-old junior Sam Kaiser.

Jenson frequently plays with the dual-nature of his career choices.

Keep those goggles on, he stressed to his students again during the recent gas properties lab, and avoid the temptation to force the kind of gas pressure that can burst glass containers.

“Remember my rule,” he said. “I don’t want to be a doctor and a teacher in the same room.”

There’s a joy in the groove he’s attained. It shows in a couple of the signs on his wall that invoke the charge of his beloved Notre Dame football team, exhorting the players to “Play like a champion today.”

His blue and gold banners say, “Teach like a champion today,” and “Heal like a champion today.”

There is “a pristine thing about Chris,” Martens said.

He did what many people can’t or won’t do. He unloosed himself from the kind of obligation that compels people to persist in their first chosen academic degrees or career choices because so much has been invested.

“When you lift those boundaries,” she said, “you have someone who is now pursuing his true love.”

To reach Joe Robertson, call 816-234-4789 or send email to jrobertson@kcstar.com.