"I believe in the power of a song — from 'Yankee Doodle' to 'We Shall Overcome,'" said performer Tom Chapin, guitar strapped over his right shoulder, facing 3,000 audience members Friday morning.

"You can become anything if you go through the public school system … and I became a folk singer," the three-time Grammy winner said to loud cheers. A graduate of Brooklyn Tech and SUNY Plattsburgh, Chapin said he believes in public education and the "power and promise of a well-rounded education." But he's against testing "that becomes so important it becomes skewed."

Alarmed by friends who were leaving teaching because of the emphasis on testing, he turned to song.

"Not on the Test," a song he wrote with John Forster and performed Friday morning, had delegates singing and cheering as the song poked fun at how students are limited to learning whatever is on "the test."

He and his friend decided to start a "guerrilla movement" against extreme testing. Chapin's Web site, which is a music video with students (http://www.notonthetest.com/), had 27,000 hits the first day.

"We had a hand in educating him and now he's educating the public," said NYSUT President Dick Iannuzzi, who stressed NYSUT's advocacy for arts in education.