Susan Walsh, Associated Press
President Barack Obama speaks in the East Room of the White House in Washington, Tuesday, Feb. 7, 2012, during the White House Science Fair. Obama hosted the second White House Science Fair celebrating the student winners of a broad range of science, technology, engineering and math (STEM) competitions from across the country.

DETROIT — Two Detroit school science projects attracted the attention of President Barack Obama on Tuesday.

The White House hosted a science fair, featuring projects by more than 100 students from across the country.

Obama visited the exhibits in the State Dining Room, and his first stop was a design for a more energy-efficient city by a team of students from the Paul Robeson, Malcolm X Academy in Detroit.

The president asked a few questions, shook hands and thanked the Detroit students for their work. Later, he commented on the project in remarks to all the students.

"There's a group of young engineers from Paul Robeson, Malcolm X Academy," Obama said. "And nobody needs to tell them the kinds of challenges that Detroit still faces. Where's my team from Detroit? In the house — there they are. Stand up. They believe in their city, and they're coming up with new ideas to keep Detroit's comeback going."

The Robeson academy is part of the Detroit Public Schools and has about 600 students in kindergarten through eighth grade.

In a statement released by the district, Robeson teacher Derek Sale said, "This project is significant to our students because it shows them by creating a walking neighborhood, you can engineer a community where crime has decreased, safety increases, and poverty is decreased as well.

"The field of engineering has provided a means for them to develop a better city in the way they wish it to be and the way they see it needs to be."

A seventh-grader from Detroit's O.W. Holmes Elementary-Middle School, Suzan Shalhout, also participated in the science fair. Her project, sponsored by the Star Base program at Selfridge Air National Guard Base, was called "Water, Water, in the Ground, Who is the Cleanest One Around?" It carried out test of tap water in various southeastern Michigan communities.

"It was really fun," the 12-year-old said. "I never thought I'd meet the president. I only thought I'd maybe see him from far away. But I never thought I'd be able to talk to him and shake hands with him. He said 'Keep up the good work' to me."

Other projects at the fair included a robot that helps older people connect with their families via Skype and a portable disaster relief shelter that could be used to house displaced people.

"It's not every day you have robots running all over your house," Obama said. "I'm trying to figure out how you got through the metal detectors."