On Saturday, the Kimmel Center in Philadelphia will offer a free, all-day festival of organ music to celebrate its own Fred J. Cooper Memorial organ in Verizon Hall.

The organ has 7,000 pipes, representing 125 distinct voices -- or ranks -- making it the largest mechanical organ in the country. It's about one-quarter the size of the massive Wanamaker Organ at Macy's in Philadelphia, the largest functioning pneumatic pipe organ in the world. (The hands-down largest organ in the world, the Boardwalk Hall Auditorium Organ in Atlantic City, is not fully functional.)

Peter Richard Conte, the Grand Court organist at Macy's, will perform "Peter and the Wolf," accompanying a life-size puppet show of Prokofiev's whimsical tale of a boy who manages to outsmart a wolf. Each character -- Peter, a cat, a bird, a duck, and a wolf -- are represented by different instruments in the symphony.The cat is a clarinet, the oboe is a duck, the French horn is the wolf, etc.

With 125 ranks of pipes, the Cooper organ -- alone -- can mimic any instrument in the orchestra.

"This organ is meant to not represent a symphony, because obviously a symphony exists in this building, but it has symphonic colors on it," said Conte. "The solo instruments aren't quite as powerful as I'd like, so I'm adding a few things to them. But I'm keeping the character of the French horn. Same with the duck and same with the cat."

The day-long celebration of the organ will also include scores for silent film comedies with Buster Keaton ("The Goat" and "Sherlock, Jr.") and a improvisational jazz ensemble.

The Philadelphia Orchestra's 2014-2015 season will focus on the organ for the month of October with a series of organ-specific concerts. "The Art of the Pipe Organ" will including a Slavic Mass, Strauss' "Also sprach Zarathustra," as featured in the film "2001: A Space Odyssey," and a special Halloween night performance of a virtual reincarnation -- the ghost, per se -- of an organ piece performed by the late Leopold Stokowski.