President Obama, who's on TV pretty much every day, recently taped a guest role for a popular cable show where he's never appeared -- Mythbusters on the Discovery Channel. In an episode airing Dec. 8, the president will challenge the hosts to test the validity of an ancient Greek legend involving reflected sunshine and fire.

It's a chance for Obama to stress the value of math and science education, a theme he focused on last week at the first White House Science Fair honoring student winners of science, technology, engineering and math competitions. The two Discovery hosts were there, too. On Mythbusters each week, they apply scientific or engineering tests to check whether widely believed notions are true.
The episode with Obama will examine the story that a Greek scientist named Archimedes set fire to an invading Roman fleet by positioning 500 soldiers on shore with polished shields that directed the sun's rays at enemy boats. Instead of troops, the TV version will use 500 high school and middle school students from Alameda, Calif.

At the White House presentation, Obama told 25 students from across the country: "I expect some of you to be back here as Nobel Prize winners." Projects included a physical therapy chair for disabled children, a solar powered car, a hydro-power water purification system and a "smart" steering wheel that beeps when a driver takes one or both hands off. Obama, noting that steering wheel sensor would know when someone was texting while driving, mentioned his daughters: "So Malia and Sasha, once they start driving, I can have this thing on there."
"Often, we don't give these victories the attention that they deserve," the president added, standing with medal-wearing teens. "When you win first place at a science fair, nobody's rushing the field or dumping Gatorade over your head." The fair reinforced a push to improve student performance in math and science as part of state and local education reforms encouraged with federal money.

President says: "I taped a special guest appearance . . . although I didn't get to blow anything up. . . . I was a little frustrated about that." -- At White House Science Fair, Oct. 19

Co-host says: "Neither Adam [Savage] or I are scientists, we're not engineers or anything of the sort. . . . Fun for us happens to involve science and satisfying our curiosity." -- Jamie Hyneman

Mythbusters audience: The show's 13 million weekly viewers include many students aged 9-14.