Obama noted that the academy was founded during the Civil War, helping to inspect the Union's ironclad ships and calibrate compasses on board.
"So, right off the bat, you guys were really useful," Obama said.
"In fact," he continued, "it's fair to say we might not be here — certainly, I would not be here."
Obama also used humor to underscore one of the primary themes of his speech: the threat to scientific research from the spending cuts under sequestration.
"Part of what's made the academy so effective is that all the scientists elected to your elite ranks are volunteers, which is fortunate because we have no money anyway," Obama quipped.
Obama went on to warn that "with the pace of technological innovation today, we can't afford to stand still for a year or two years or three years."
The sequester is "hitting our scientific research," he said. "Instead of racing ahead on the next cutting edge discovery, many of our scientists are wondering if they'll get to start any new projects, any new research projects over the next few years, which means that we could use a year, two years of science and research as a practical matter because of misguided priorities here in this town."
The president also praised the gathered assembly of scientists, saying they were role models to students like the ones who gathered last week at the White House for the annual science fair.
"They were all dreaming to grow up and be just like you — maybe with a little less gray hair, but they shared your passion," Obama said.