In a lab at the University of Colorado, first-year students channel their inner da Vincis, applying engineering principles to build games that double as exercise.

One team, for example, is engineering a video game that emulates Nintendo's Mario Kart -- but instead of pushing a remote-control button, participants must pedal a bike. For the prototype, the students scored a tricycle from Craigslist for $10 that they've linked up to the game.

It's hands-on classes like this one that are helping retain more engineering students. In fact, the design lab can boost graduation rates by as much as 20 percent and is especially effective among female and under-represented minority students, according to the university.

As the nation faces a shortage of graduates from science, technology, engineering and math fields, CU will use a $4.3 million grant to find out why college students are leaving STEM majors. The last time research on the problem was conducted was two decades ago.

When the original study took place in the early 1990s, the rate of students leaving STEM majors ranged from 40 to 60 percent. Those rates have remained persistently stubborn, said Anne-Barrie Hunter, co-director of Ethnography and Evaluation Research at CU and principal investigator for the Colorado research team.

What causes 'switchers' vs. 'persisters'

CU has positioned itself as a leader in STEM education, recently launching its Center for STEM Learning, which officially formed in December and helps coordinate more than 75 existing programs on the campus.

The study -- funded by the National Science Foundation and the Alfred P. Sloan Foundation -- is the first to be run out of CU's new STEM center.

The Boulder campus is partnering with the University of Wisconsin-Madison for the research project.

The research will include combing through transcripts to find out if there are certain classes -- like notoriously tough organic chemistry -- that trigger students to ditch their majors. Researchers will also interview hundreds of undergraduates, course instructors and observe classroom teaching practices. At the conclusion of the study, the research team plans to publish a book.

For the original study, researchers interviewed more than 400 undergraduates who were grouped as "switchers" or "persisters," according to Elaine Seymour, who co-led the original research team and is involved with the upcoming project. Both groups of students were equally bright and faced the same sets of challenges, according to the findings.

"What we discovered was that an incoming interest in the sciences was dissipated over the course of the first two years by the way the courses were taught," Seymour said. "The teaching in those days was predominantly stand-and-deliver lecturing."

Their research resulted in the 1997 book "Talking about Leaving: Why Undergraduates Leave the Sciences," which has become a seminal text in the field of STEM education.

STEM: Learning 'how the world works'

Nikki Machalek, a biological and chemical engineering freshman at CU, has aspirations to work in a lab or go into medicine and said she plans to stick with her coursework no matter how challenging the classes become.

"STEM fields help you understand how the world around us works," she said while tooling with her team's game design.

In Katie Siek's first-year engineering projects class Thursday, teams of students used programming, electronic and mechanical engineering skills to build prototypes of their games that could be enjoyed by a diverse audience, ranging from children to senior citizens.

Siek said the students in her course are able to draw from what they're learning in tough introductory courses such as physics or calculus and apply theories to their projects, helping them see the big picture.

Other students in the design lab are creating a game of dodge ball, where gamers need to duck oncoming images of balls, and yet another team is working on a game that requires kickboxing motions to fend off zombies.

Contact Camera Staff Writer Brittany Anas at 303-473-1132 or anasb@dailycamera.com.