President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

U.S. President Barack Obama greets Jayla Mae Dogan, Ashley Cassie Thomas, and Lucas Cain Beal, all 13, of Detroit, Michigan, who are part of a team who focused on designing a city around the theme of “Fuel Your Future: Imagine New Ways to Meet Our Energy Needs and Maintain a Healthy Planet”, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. (Photo by Molly Riley-Pool/Getty Images)

U.S. President Barack Obama watches a robot with Robert Knight III (L), Morgan Ard (3L) and Titus Walker (C), eighth-grade students at Monroeville Jr. High School in Monroeville, Alabama, who won high honors at the South BEST robotics competition, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. (Photo by Molly Riley-Pool/Getty Images)

President Barack Obama discusses a lightweight portable disaster relief shelter designed by Jessica D'Esposito (R), Colton Newton (2L) and Anna Woolery from Petersburg, Indiana, representing the Pike Central High School InvenTeam, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. (Photo by Molly Riley-Pool/Getty Images)

U.S. President Barack Obama talks with Ana Nieto (R) of Presidio, Texas, team leader of Team America Rocketry Challenge (TARC) along with teammates Janet Nieto (2nd L) and and Gwynelle Condino, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. (Photo by Molly Riley-Pool/Getty Images)