After speeding through college and graduate school, Jo Handelsman became a professor of plant pathology at the University of Wisconsin–Madison when she was just 26. "I was so unprepared," Handelsman recalls with a shudder. "We are extremely well prepared to do research. But that's not all we do as faculty."

She had no training for perhaps the scariest task of all: teaching. When Handelsman first entered the classroom, she lectured at her students, like most of her colleagues before her. "We all go into the classroom and simply do what was done to us. That's not a very scientific way to go about it," she says. "We would never do that in our research."

As she stood terrified in front of those students, Handelsman had no idea that, two decades later, she would be known nationwide for her efforts to improve science teaching.

The gap between what Handelsman was telling students—a lot—and what they were taking in—very little—became clear when she started teaching a class for 30 undergraduate nonscience majors. The breaking point came when she tried to teach the students how to prove that a microbe was the cause of a disease. "It just felt so dry, so mechanical, that I finally said to them, 'You guys just have to do this.'" At the next class, Handelsman arrived with Petri dishes, toothpicks, and sick plants. "At first, they all just stared at me and had no idea of how to proceed. I told them to talk to each other." The room erupted. "They were acting just like scientists," Handelsman recalls proudly. "That was the moment that I realized that there really is another way to teach."

Handelsman calls that way "scientific teaching." She draws on evidence-based studies to create a "toolbox" to improve undergraduate science teaching, such as active learning, mentoring, classroom diversity, and self-correction through feedback—lessons she has developed since her appointment as an HHMI professor in 2002. A good lesson incorporates the best aspects of science itself: the rigor, creativity, and dynamism of a scientific community and the thrill of the experimental chase, she says.

As an advocate for teaching reform, Handelsman has been a regular co-organizer of the Summer Institute on Undergraduate Education in Biology, sponsored by the National Academy of Sciences and HHMI, among other organizations. The intensive, week-long course brings together faculty from universities across the country to work on integrating research and modern learning techniques into classes that help students understand how scientists think.

Handelsman moved from Wisconsin to Yale University in January 2010. She says her reappointment as an HHMI professor will allow her to sharpen her scientific teaching "toolkit" and promote its use through the Scientific Teaching Fellows Program and the Summer Institute. Graduates of these programs will be dispatched as ambassadors to regional Summer Institutes that planners hope will spread the word about scientific teaching nationwide.

She also hopes to take on the issue of faculty diversity. Since white men are the norm among faculty on most college campuses, women and people from minority groups sometimes feel out of place, Handelsman says, an attitude that she has seen reflected in counterproductive ways in science classrooms. To try to address the origins of those feelings head-on, Handelsman will work with the drama schools at both Wisconsin and Yale to create and perform short plays that dramatize diversity issues in the classroom and provoke discussion among science faculty and students.