When President Barack Obama arrived on campus in October to deliver a speech on clean energy, his motorcade made a detour before arriving at Kresge Auditorium. Accompanied by Governor Deval Patrick and Senator John Kerry, the president dropped in at Building 13, where he visited two labs. In the first, he met four researchers who had set up displays and equipment to demonstrate their ongoing work on new energy technologies. Then he proceeded next door, to the lab of professor Vladimir Bulovic, who demonstrated high-efficiency, long-lasting light bulbs based on quantum-dot technology. The tour, led by President Susan Hockfield and MIT Energy Initiative director Ernest Moniz, was a first for a sitting president--and Obama was clearly fired up by what he saw.

"You just get excited being here, seeing these extraordinary young people," he told the crowd packed into Kresge afterward, citing work that could lead to windows that generate electricity, batteries that are grown by viruses, efficient new lighting systems that rely on nanotechnology, and ways of storing energy from offshore windmills so that it can be delivered even when the air is still.

"That was neat stuff," he said.

The researchers who displayed their work to the president were impressed by his interest, understanding, and good humor. "He was very responsive, and an incredibly warm person," says chemical-­engineering professor Paula Hammond '84, PhD '93, one of the lucky five. "He understood the potential of what we were doing and asked very specific questions," she says.

"It seemed like he had a really good time, that he actually found the whole experience quite stimulating," says Marc Baldo, an associate professor of electrical engineering, who demonstrated technology that uses coated glass to concentrate solar energy. "I was a little nervous," Baldo says, "but I got the impression that he's used to walking into rooms full of nervous people, and he just put everyone at ease."

In addition to demonstrating his group's work on the concentrating solar devices, Baldo took the opportunity to showcase projects that benefited from the stimulus bill Obama pushed through as one of his first priorities after assuming office. "I'm director of a center here--the Center for Excitonics--that's funded with $20 million of stimulus money," Baldo says, adding that the center currently includes 38 graduate students and postdocs. "I talked about the impact of funding this kind of fundamental research. He seemed very receptive to that."

Hammond, along with research collaborator Angela Belcher, demonstrated work on using genetically engineered viruses to produce self-assembling solar cells and batteries. "When we described the self-assembly process, he asked several very intelligent questions, about the scalability of the process and so on," says Hammond.

Joining Hammond and Belcher in their presentation were two of their graduate students, Rebecca Lynn Ladewski and Lieutenant Colonel John Burpo, who has completed two tours in Iraq and was an Eni-MIT Energy Fellow in 2008-'09."It was a true honor to meet the president, both as a scientifically interested politician and as my commander in chief," says Burpo.