For a president who promotes technology at every opportunity, Barack Obama often strikes an awed, self-effacing pose in the presence of technicians, scientists and high tech machinery.

“If I’m nodding, you should just assume that everything you said is going completely over my head,” he once told winners of a New York science fair.

Still, he loves the stuff.

At no point has his inner geek been more evident than on Tuesday as he mischievously — “The Secret Service is going to be mad at me about this” — helped fire an eighth-grader’s award winning high-speed marshmallow air cannon at the drapes of the White House’s elegant State Dining Room.

From factory floors to classrooms, from high-tech centers to the White House residence itself, Obama steeps himself in the innovative, sometimes feigning interest while at others showing genuine delight.

He dons safety goggles to tour manufacturing plants with state of the art equipment. He steps gingerly around scooting robots built by teenage engineers. And, like many a dad, he helps his daughters with their science projects, even dropping eggs from the White House’s Truman Balcony to test the optimal soft landing.