In the pre-engineering classrooms at Pittsburgh Allderdice High School, students huddle over tables and computers, mixing laughter and science, savoring the process of discovery.

Lucky to be admitted to the Squirrel Hill school's magnet program, they experiment with shipbuilding, fish farming, manufacturing, flight simulators, global positioning systems and wind tunnels, learning how to apply technology to challenges they'll face in the workplace.

"I use anything I can find for models," including wire and grass-trimmer string, said Doug Rakoczy, a junior who builds replicas of roller coasters and aspires to be an "Imagineer" for the Walt Disney Co.

This is the new face of vocational education -- now called career and technical education, or CTE -- and Pittsburgh Public Schools Superintendent Mark Roosevelt wants to infuse more of it into his overhaul of city high schools.

The lines between CTE and college-bound study have blurred because of the increasingly technical nature of the global economy, with many educators concluding that students need the same knowledge and skills whether they're going to work or college after graduation.

The stigma attached to vocational education is disappearing, if not as quickly as some advocates would like.

Indeed, a technical background may give CTE students a leg up career-wise on students in regular academic tracks, said Steve DeWitt, senior director of public policy at the Association for Career and Technical Education in Alexandria, Va.

Also, research has shown that hands-on CTE programs capture some students' interest in a way other classes don't.

Some students best understand and appreciate mathematics when they can use it to mix paints in an auto-body class at Pittsburgh Brashear High School in Beechview or design cardboard ships, to be laden with a cargo of ceramic tiles, in Allderdice's pre-engineering program. The opportunity to apply knowledge in such ways is so powerful, educators believe, that it may keep students from dropping out.

"Career and technical education really does provide the link between what you're learning and why you're learning it," said Jason Kiker, education research analyst at the CTE association.

The result is a renewed interest in CTE in Pittsburgh and elsewhere, even though the federal No Child Left Behind Act, which has led to a strong focus on traditional math and reading instruction, has made for a difficult balancing act.

Districts also are finding it necessary to choose from an ever-broadening array of CTE courses, from the traditional welding and masonry offerings to the cutting-edge sciences.

With about 2,000 students now enrolled in CTE courses, Pittsburgh school officials plan to drop programs they consider outdated, shore up others and launch new ones.

"Right now, I do not believe we have a CTE program," school board member Theresa Colaizzi said. "I think we have bits and pieces of a good program, but I really don't think we have a good, strong CTE program at all."

Julia Stewart, executive director of career and technical education, wouldn't say which of the 25 to 30 current programs she intends to eliminate. But she cited plans to add diesel mechanics, aviation technology and various sciences, complementing the state Department of Education's list of occupations with high demand for workers.

She's also said that she intends to eliminate duplication of courses and ensure that students receive the state-required number of instructional hours, something that doesn't always happen now.

The district must provide the required hours to receive reimbursement for CTE programs. Bumping up instruction also would help students get the most out of the programs, including certification to work in some fields.

The district hopes to strengthen CTE offerings with new partnerships with trade unions, businesses and other organizations and to seek additional agreements with post-secondary institutions to give students credit or advanced standing for CTE work.

Ms. Colaizzi called for centrally locating CTE programs to make them more accessible to students citywide and foster a stronger commitment to the programs. Now, she said, the programs are scattered around the city, and principals' commitment to them varies.

Nationwide, the quality of all kinds of CTE programs has improved over the past decade with the input of industry groups, improved teacher training and a closer link with academic course work, said Gene Bottoms, senior vice president of the Southern Regional Education Board, an Atlanta-based nonprofit group.

Districts can acquire ready-made curricula in such fields as pre-engineering, biotechnology and banking, he said.

Done well, CTE programs can give students various options upon graduation: immediate entry to the workplace, apprenticeship with a trade union or admission to a two- or four-year school.

Jesse Blosl, a senior in the auto mechanics program at Brashear, said he plans to enroll in the PowerSport Institute at Ohio Technical College to study motorcycle repair. Like the pre-engineering students at Allderdice, he's motivated by the challenge of diagnosing a problem and devising a solution.

"You have to do it without messing anything else up," he noted.

The Allderdice program, so popular that some applicants are turned away each year, exposes students to 16 types of engineering. A large tank of koi facilitates a study of tilapia farming; a lamp nurtures tomato plants sprung from a 16th generation of seeds; and students puzzle over the design of the cardboard boats, seeing how many tiles they can load before the vessels capsize.

"The record is 54," teacher Al Puskaric said.

Auto mechanics and pre-engineering both require knowledge of math, the ability to decipher technical text, knowledge of computers and teamwork. The similarities drive home what some advocates say is the importance of educating all students to the same level, regardless of their career plans.

"The difference could be the way students are exposed to that core set of knowledge and skills," said Daria Hall, assistant director for K-12 policy at the Education Trust, an advocacy group in Washington, D.C.

In a sign of how far vocational training has come -- and how attitudes toward it are changing -- CTE students these days may take the highest-level courses available in high school or enroll in academic college courses part-time. The purpose of CTE programs is not to lock students into vocations, but to provide opportunities or "pathways" to the future.

"IT [information technology] is a pathway. Engineering is a pathway," said Gene Longo, a Pittsburgh-area native who manages Cisco Networking Academy in the United States and Canada. The academy is an IT program that enrolls 600,000 students worldwide, including some in the Pittsburgh schools.