In the auditorium of Porter Middle School in Granada Hills, studio musician Tom Edwards held up a 6-inch harmonica and asked the audience of 70 students an obvious question: "What do you think it is?"
One of the students guessed: "a harmonica?"
Edwards turned to Michael Rotman, chairman of the music department at Porter, and said, "They are smart."
"Do you know what kind of harmonica?" Edwards asked.
The 65-year-old musician, whose credits include the score for the Oscar-winning movie "Dances With Wolves" and the theme from the TV series "The Rockford Files," answered his own question: "It's a diatonic harmonica."
After a brief explanation, he then proceeded to perform "Amazing Grace" with the flair of Liberace.
The restless teenage audience was suddenly captivated.
The diatonic harmonica was one of six types Edwards demonstrated to the middle school audience in what has become an annual event.