Todd Mowry planned on being a medical doctor before he realized his passion for computers during the summer of his senior year in high school.

He made that life-changing discovery 24 years ago as a student at the Pennsylvania Governor's School for the Sciences at Carnegie Mellon University.

Today, Dr. Mowry is a professor of computer science at Carnegie Mellon where the summer science program for talented high school seniors is still going strong.

"I came back to CMU because it's the No. 1-ranked computer science department and the best place in the world to do computer science," said Dr. Mowry, who earned a doctorate at Stanford University.

This summer marks the 25th year of the Governor's School for the Sciences at the university, a program that has inspired a generation of high school seniors to pursue science careers during an age of unprecedented technological advances.

Statewide, there are eight governor's schools that focus on fields ranging from business to medicine, agriculture and the arts. Two are based at the University of Pittsburgh -- Pennsylvania Governor's School for Health Care and Pennsylvania Governor's School for International Studies. Combined, they have 15,500 alumni. The first -- Pennsylvania Governor's School for the Arts -- was founded in 1973.

While most of the 2,179 alumni of the governor's schools at Carnegie Mellon are working as scientists, engineers, science professors and medical doctors, the program taught others that their strengths lay elsewhere and they chose different careers.

"Our alumni includes a rocket scientist who works at the jet propulsion laboratory for NASA," said Barry Luokkala, director of Carnegie Mellon's summer program.

Rising high school seniors from across the state who attend the intensive five-week program at Carnegie Mellon receive no grades or academic credit for their work. What they do receive, though, is a chance to work and learn, probably for the first time, in an environment where everyone is academically talented and excited about math and science.

The state pays about $2,500 for each student to attend the session, which ended last week.

"I had AP physics, but this is a different type of physics," said Cecily Sunday, 17, of McCandless, a senior at North Allegheny High School.

"That's why I like this program. It's not just chemistry; it's organic chemistry. It's not just physics, but special relativity. It's not just biology; it's HIV and molecular. They do a really good job of teaching stuff that people aren't familiar with," Cecily said.

The five areas covered during the five weeks include physics, math, chemistry, computer science and biology. But it's a far more in-depth study than many high school courses provide. At Carnegie Mellon, students spend their days figuring how to cure diseases and learning how the brain works.

They work in teams, conducting laboratory experiments such as exploring whether light is a wave or a particle, or finding mechanical chaos to record it and see how it behaves, or searching for ways to make a pendulum swing forever.

The 100 students admitted to the Governor's School for the Sciences this year were chosen from a pool of 530 applicants. All are college-bound. Over the years, many who attended have been accepted to the best colleges and universities in the country.

When Dr. Mowry entered the University of Virginia in 1984, he said the first few computer courses he took were less than inspiring, but because of his summer experience at Carnegie Mellon, he knew what was down the road and that kept him from changing majors.

"It was an important milestone in my professional life," he said.

Eun-Hyung Lee, a medical doctor who specializes in pulmonary and critical care at the University of Rochester, also participated in the 1983 Carnegie Mellon summer program.

"Some of my best friends are in that group," she said. "It played a significant role in my career.

"That summer experience encouraged me to go into the field I'm in. It excited me to want to pursue a career in clinical research even more."

Andreea Manolache, 17, of Upper St. Clair, is undecided on whether she'll be an architect, an engineer or biologist. She's hoping the time she spent this summer at Carnegie Mellon will help her decide.

"I wanted to be challenged outside of school," she said. "[Upper St. Clair] is a pretty good school. But I felt like the summers were kind of empty of any challenge. I just really wanted to learn.

"This is excellent," she said of the governor's school. "It's the most fun summer I've ever had. This is a lot harder. It's a lot more intense."

First Published: July 31, 2007, 3:15 a.m.